path: root/doc/rfc/rfc9553.txt

Internet Engineering Task Force (IETF)                       R. Stepanek
Request for Comments: 9553                                      Fastmail
Category: Standards Track                                    M. Loffredo
ISSN: 2070-1721                                                  IIT-CNR
                                                                May 2024


            JSContact: A JSON Representation of Contact Data

Abstract

   This specification defines a data model and JavaScript Object
   Notation (JSON) representation of contact card information that can
   be used for data storage and exchange in address book or directory
   applications.  It aims to be an alternative to the vCard data format
   and to be unambiguous, extendable, and simple to process.  In
   contrast to the JSON-based jCard format, it is not a direct mapping
   from the vCard data model and expands semantics where appropriate.
   Two additional specifications define new vCard elements and how to
   convert between JSContact and vCard.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc9553.

Copyright Notice

   Copyright (c) 2024 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Revised BSD License text as described in Section 4.e of the
   Trust Legal Provisions and are provided without warranty as described
   in the Revised BSD License.

Table of Contents

   1.  Introduction
     1.1.  Motivation and Relation to vCard, jCard, and xCard
     1.2.  Notational Conventions
     1.3.  Data Type Notations
       1.3.1.  Objects and Properties
       1.3.2.  Type Signatures
       1.3.3.  Property Attributes
       1.3.4.  The @type Property
     1.4.  Common Data Types
       1.4.1.  Id
       1.4.2.  Int and UnsignedInt
       1.4.3.  PatchObject
       1.4.4.  Resource
       1.4.5.  UTCDateTime
     1.5.  Common Properties
       1.5.1.  contexts
       1.5.2.  label
       1.5.3.  pref
       1.5.4.  phonetic
     1.6.  Internationalization
       1.6.1.  Free-Form Text
       1.6.2.  URIs
     1.7.  Validating JSContact
       1.7.1.  Case-Sensitivity
       1.7.2.  IANA-Registered Properties
       1.7.3.  Reserved Properties
       1.7.4.  Unknown Properties
       1.7.5.  Enumerated Values
     1.8.  Vendor-Specific Extensions
       1.8.1.  Vendor-Specific Properties
       1.8.2.  Vendor-Specific Values
     1.9.  Versioning
       1.9.1.  Version Format and Requirements
       1.9.2.  Current Version
   2.  Card
     2.1.  Metadata Properties
       2.1.1.  @type
       2.1.2.  version
       2.1.3.  created
       2.1.4.  kind
       2.1.5.  language
       2.1.6.  members
       2.1.7.  prodId
       2.1.8.  relatedTo
       2.1.9.  uid
       2.1.10. updated
     2.2.  Name and Organization Properties
       2.2.1.  name
       2.2.2.  nicknames
       2.2.3.  organizations
       2.2.4.  speakToAs
       2.2.5.  titles
     2.3.  Contact Properties
       2.3.1.  emails
       2.3.2.  onlineServices
       2.3.3.  phones
       2.3.4.  preferredLanguages
     2.4.  Calendaring and Scheduling Properties
       2.4.1.  calendars
       2.4.2.  schedulingAddresses
     2.5.  Address and Location Properties
       2.5.1.  addresses
     2.6.  Resource Properties
       2.6.1.  cryptoKeys
       2.6.2.  directories
       2.6.3.  links
       2.6.4.  media
     2.7.  Multilingual Properties
       2.7.1.  localizations
     2.8.  Additional Properties
       2.8.1.  anniversaries
       2.8.2.  keywords
       2.8.3.  notes
       2.8.4.  personalInfo
   3.  IANA Considerations
     3.1.  Media Type Registration
     3.2.  Creation of the JSContact Registry Group
     3.3.  Registry Policy and Change Procedures
       3.3.1.  Preliminary Community Review
       3.3.2.  Submit Request to IANA
       3.3.3.  Designated Expert Review
       3.3.4.  Change Procedures
     3.4.  Creation of the JSContact Version Registry
       3.4.1.  JSContact Version Registry Template
       3.4.2.  Initial Contents of the JSContact Version Registry
     3.5.  Creation of the JSContact Properties Registry
       3.5.1.  JSContact Properties Registry Template
       3.5.2.  Initial Contents of the JSContact Properties Registry
     3.6.  Creation of the JSContact Types Registry
       3.6.1.  JSContact Types Registry Template
       3.6.2.  Initial Contents of the JSContact Types Registry
     3.7.  Creation of the JSContact Enum Values Registry
       3.7.1.  JSContact Enum Values Registry Property Template
       3.7.2.  JSContact Enum Values Registry Value Template
       3.7.3.  Initial Contents of the JSContact Enum Values Registry
   4.  Security Considerations
     4.1.  JSON Parsing
     4.2.  URI Values
   5.  References
     5.1.  Normative References
     5.2.  Informative References
   Authors' Addresses

1.  Introduction

   This document defines a data model for contact card data normally
   used in address book or directory applications and services.  It aims
   to be an alternative to the vCard data format [RFC6350].

   The key design considerations for this data model are as follows:

   *  The data model and set of attributes should be mostly compatible
      with the model defined for the vCard data format [RFC6350] and
      extensions [RFC6473] [RFC6474] [RFC6715] [RFC6869] [RFC8605].  The
      specification should add new attributes or value types where
      appropriate.  Not all existing vCard definitions need an
      equivalent in JSContact, especially if the vCard definition is
      considered to be obsolete or otherwise inappropriate.  Conversion
      between the data formats need not fully preserve semantic meaning.

   *  The attributes of the card data must be described as simple key-
      value pairs to reduce the complexity of the representation of the
      card data.

   *  The data model should avoid all ambiguities and make it difficult
      to make mistakes during implementation.

   *  Extensions, such as new properties and components, MUST NOT lead
      to a required update of this document.

   The representation of this data model is defined in the Internet JSON
   (I-JSON) format [RFC7493], which is a strict subset of the JSON data
   interchange format [RFC8259].  Using JSON is mostly a pragmatic
   choice: its widespread use makes JSContact easier to adopt, and the
   availability of production-ready JSON implementations eliminates a
   whole category of parser-related interoperability issues.

1.1.  Motivation and Relation to vCard, jCard, and xCard

   The vCard data format [RFC6350] is an interchange format for contacts
   data between address book service providers and vendors.  However,
   this format has gone through multiple specification iterations with
   only a subset of its deprecated version 3 [RFC2426] being widely in
   use.  Consequently, products and services use an internal contact
   data model that is richer than what they expose when serializing that
   information to vCard.  In addition, service providers often use a
   proprietary JSON representation of contact data in their APIs.

   JSContact provides a standard JSON-based data model and
   representation of contact data as an alternative to proprietary
   formats.

   At the time of writing this document, several missing features in
   vCard were brought to the attention of the authors such as social
   media contacts, gender pronouns, and others.  This highlights how
   vCard is not perceived as an evolving format and, consequently,
   hasn't been updated for about ten years.  JSContact addresses these
   unmet demands and defines new vCard properties and parameters to
   allow interchanging them in both formats.

   Two additional documents define the relation of JSContact and vCard:
   [RFC9554] defines new vCard properties and parameters, and [RFC9555]
   defines how to convert JSContact data from and to vCard.

   The xCard [RFC6351] and jCard [RFC7095] specifications define
   alternative representations for vCard data in XML and JSON formats,
   respectively.  Both explicitly aim to not change the underlying data
   model.  Accordingly, they are regarded as equal to vCard in the
   context of this document.

1.2.  Notational Conventions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

   The ABNF definitions in this document use the notations of [RFC5234].
   ABNF rules not defined in this document are defined in either
   [RFC5234] (such as the ABNF for CRLF, WSP, DQUOTE, VCHAR, ALPHA, and
   DIGIT) or [RFC6350].

1.3.  Data Type Notations

   This section introduces the notations and terminology used to define
   data types in JSContact.

   The underlying format for JSContact is JSON, so its data types also
   build on JSON values.  The terms "object" and "array" as well as the
   four primitive types ("strings", "numbers", "booleans", and "null")
   are to be interpreted as described in Section 1 of [RFC8259].  All
   JSContact data MUST be valid according to the constraints given in
   I-JSON [RFC7493].  Unless otherwise noted, all member names in JSON
   objects and all string values are case-sensitive.  Within the context
   of JSON objects, the term "key" is synonymous with "member name" as
   defined in Section 1 of [RFC8259].

1.3.1.  Objects and Properties

   JSContact defines data types for contact information such as
   addresses or names.  This information typically consists of multiple
   related elements; for example, a personal name and surname together
   form a name.  These related elements are organized in JSContact
   objects.  A JSContact object is a JSON object that has the following:

   1.  A unique type name registered in the IANA "JSContact Types"
       registry (Section 3.6).

   2.  One or more object members for which the name and allowed value
       types are specified.  Such members are called "properties".

   3.  One property named @type with a string value that matches the
       type name of the JSContact object.  In general, this property
       does not need to be set explicitly as outlined in Section 1.3.4.

   The following sections specify how to define JSContact object types.
   Sections 1.7 and 1.8 then define the exact requirements for property
   names.

   The next paragraph illustrates how a JSContact object is defined.
   The names "Foo" and "baz" are only for demonstration and have no
   meaning outside the example.

      A Foo object has the following properties:

      @type: String.  The JSContact type of the object.  The value MUST
         be "Foo", if set.

      baz: Number (mandatory).  The baz level of the contact.  The value
         MUST be an integer greater than 0 and less than 10.

   The above paragraph illustrates the following:

   *  It defines a JSContact object type named "Foo" that has two
      properties, named "@type" and "baz".

   *  The @type property adheres to the rules outlined in Section 1.3.4.
      Because of this, it is neither defined to be mandatory nor
      optional, as this depends on how the Foo object type is used.

   *  The baz property value MUST be valid according to the definition
      of the Number type.

   *  The property has one attribute, "mandatory", which specifies that
      the property MUST be present for a value of the Foo object type to
      be valid.

   *  The free-text description of the baz property describes the
      semantics and further restrictions for its values.

1.3.2.  Type Signatures

   Type signatures are given for all JSON values and JSContact
   definitions in this document.  The following conventions are used:

   String:  The JSON string type.

   Number:  The JSON number type.

   Boolean:  The JSON boolean type.

   A[B]:  A JSON object where all keys are of type A and all values are
      of type B.

   A[]:  A JSON array of values of type A.

   A|B:  The value is either of type A or of type B.

   *:  The type is undefined (the value could be any type, although
      permitted values may be constrained by the context of this value).

   Section 1.4 defines common data types, including signed or unsigned
   integers and dates.

1.3.3.  Property Attributes

   Object properties may also have a set of attributes defined along
   with the type signature.  These have the following meanings:

   mandatory:  The property MUST be set for an instance of this object
      to be valid.

   optional:  The property can, but need not, be set for an instance of
      this object to be valid.

   default:  This is followed by a JSON value.  That value will be used
      for this property if it is omitted.

   defaultType:  This is followed by the name of a JSContact object
      type.  A property value of JSContact object type is expected to be
      of this named type, in case it omits the @type property.

1.3.4.  The @type Property

   @type: String.  The JSContact type of a JSON object.  It MUST match
      the type name of the JSContact object of which the JSON object is
      an instance of.

   The purpose of the @type property is to help implementations identify
   which JSContact object type a given JSON object represents.
   Implementations MUST validate that JSON objects with this property
   conform to the specification of the JSContact object type of that
   name.

   In many cases, the @type property value is implied by where its
   object occurs in JSContact data.  Assuming that both A and B are
   JSContact object types:

   *  An object that is set as the value for a property with type
      signature "A" MAY have the @type property set.  If the @type
      property is not set, then its value is implied to be A by the
      property definition.

   *  An object that is set as the value for a property with type
      signature "A|B (defaultType: A)" MAY have the @type property set
      if it is an instance of A.  It MUST have the @type property set if
      it is an instance of B.  If, instead, the defaultType attribute is
      not defined, then the @type property MUST also be set for A.

   *  An object that is not the value of a property, such as the topmost
      object in JSON data (directly or as a member of an array), MUST
      have the @type property set.

1.4.  Common Data Types

   In addition to the standard JSON data types, a couple of additional
   data types are common to the definitions of JSContact objects and
   properties.

1.4.1.  Id

   Where "Id" is given as a data type, it means a String of at least 1
   and a maximum of 255 octets in size, and it MUST only contain
   characters from the "URL and Filename Safe" base64url alphabet, as
   defined in Section 5 of [RFC4648], excluding the pad character ("=").
   This means the allowed characters are the ASCII alphanumeric
   characters ("A-Za-z0-9"), hyphen ("-"), and underscore ("_").

   In many places in JSContact, a JSON map is used where the map keys
   are of type Id and the map values are all the same type of object.
   This construction represents an unordered set of objects, with the
   added advantage that each entry has a name (the corresponding map
   key).  This allows for more concise patching of objects and, when
   applicable, for the objects in question to be referenced from other
   objects within the JSContact object.  The map keys MUST be preserved
   across multiple versions of the JSContact object.

   Unless otherwise specified for a particular property, there are no
   uniqueness constraints on an Id value (other than, of course, the
   requirement that you cannot have two values with the same key within
   a single JSON map).  For example, two Card (Section 2) objects might
   use the same Ids in their respective photos properties.  Or within
   the same Card, the same Id could appear in the emails and phones
   properties.  These situations do not imply any semantic connections
   among the objects.

1.4.2.  Int and UnsignedInt

   Where "Int" is given as a data type, it means an integer in the range
   -2^53+1 <= value <= 2^53-1, which is the safe range for integers
   stored in a floating-point double, represented as a JSON Number.

   Where "UnsignedInt" is given as a data type, it means an integer in
   the range 0 <= value <= 2^53-1 represented as a JSON Number.

1.4.3.  PatchObject

   A PatchObject is of type "String[*]" and represents an unordered set
   of patches on a JSON object.  Each key is a path represented in a
   subset of the JSON Pointer format [RFC6901].  The paths have an
   implicit leading "/", so each key is prefixed with "/" before
   applying the JSON Pointer evaluation algorithm.

   A patch within a PatchObject is only valid if all the following
   conditions apply:

   1.  The pointer MAY reference inside an array, but if the last
       reference token in the pointer is an array index, then the patch
       value MUST NOT be null.  The pointer MUST NOT use "-" as an array
       index in any of its reference tokens (i.e., you MUST NOT insert/
       delete from an array, but you MAY replace the contents of its
       existing members.  To add or remove members, one needs to replace
       the complete array value).

   2.  All reference tokens prior to the last (i.e., the value after the
       final slash) MUST already exist as values in the object being
       patched.  If the last reference token is an array index, then a
       member at this index MUST already exist in the referenced array.

   3.  There MUST NOT be two patches in the PatchObject where the
       pointer of one is the prefix of the pointer of the other, e.g.,
       "addresses/1/city" and "addresses".

   4.  The value for the patch MUST be valid for the property being set
       (of the correct type and obeying any other applicable
       restrictions), or if null, the property MUST be optional.

   The value associated with each pointer determines how to apply that
   patch:

   *  If null, remove the property from the patched object.  If the key
      is not present in the parent, this is a no-op.

   *  If non-null, set the value given as the value for this property
      (this may be a replacement or addition to the object being
      patched).

   A PatchObject does not define its own @type (Section 1.3.4) property.
   Instead, the @type property in a patch MUST be handled as any other
   patched property value.

   Implementations MUST reject a PatchObject in its entirety if any of
   its patches are invalid.  Implementations MUST NOT apply partial
   patches.

1.4.4.  Resource

   The Resource data type defines a resource associated with the entity
   represented by the Card, identified by a URI [RFC3986].  Later in
   this document, several property definitions refer to the Resource
   type as the basis for their property-specific value types.  The
   Resource type defines the properties that are common to all of them.
   Property definitions making use of Resource MAY define additional
   properties for their value types.

   A Resource object has the following properties:

   @type: String.  The JSContact type of the object.  The value MUST NOT
      be "Resource"; instead, the value MUST be the name of a concrete
      resource type (see Section 2.6).

   kind: String (optional).  The kind of the resource.  The allowed
      values are defined in the property definition that makes use of
      the Resource type.  Some property definitions may change this
      property from being optional to mandatory.

   uri: String (mandatory).  The resource value.  This MUST be a _URI_
      as defined in Section 3 of [RFC3986].

   mediaType: String (optional).  The media type [RFC2046] of the
      resource identified by the uri property value.

   contexts: String[Boolean] (optional).  The contexts in which to use
      this resource.  Also see Section 1.5.1.

   pref: UnsignedInt (optional).  The preference of the resource in
      relation to other resources.  Also see Section 1.5.3.

   label: String (optional).  A custom label for the value.  Also see
      Section 1.5.2.

1.4.5.  UTCDateTime

   The UTCDateTime type is a String in "date-time" format [RFC3339],
   with further restrictions that any letters MUST be in uppercase and
   the time offset MUST be the character "Z".  Fractional second values
   MUST NOT be included unless they are non-zero, and they MUST NOT have
   trailing zeros to ensure there is only a single representation for
   each date-time.

   For example, "2010-10-10T10:10:10.003Z" is conformant, but
   "2010-10-10T10:10:10.000Z" is invalid; the correct encoding is
   "2010-10-10T10:10:10Z".

1.5.  Common Properties

   Most of the properties in this document are specific to a single
   JSContact object type.  Such properties are defined along with the
   respective object type.  The properties in this section are common to
   multiple data types and are defined here to avoid repetition.  Note
   that these properties MUST only be set for a JSContact object if they
   are explicitly mentioned as allowable for this object type.

1.5.1.  contexts

   contexts: String[Boolean].  The contexts in which to use the contact
      information.  For example, someone might have distinct phone
      numbers for work and private contexts and may set the desired
      context on the respective phone number in the phones
      (Section 2.3.3) property.

      This section defines common contexts.  Additional contexts may be
      defined in the properties or data types that make use of this
      property.  The enumerated (Section 1.7.5) common context values
      are:

      *  private: the contact information that may be used in a private
         context.

      *  work: the contact information that may be used in a
         professional context.

1.5.2.  label

   label: String.  The labels associated with the contact data.  Such
      labels may be set for phone numbers, email addresses, and other
      resources.  Typically, these labels are displayed along with their
      associated contact data in graphical user interfaces.  Note that
      succinct labels are best for proper display on small graphical
      interfaces and screens.

1.5.3.  pref

   pref: UnsignedInt.  A preference order for contact information.  For
      example, a person may have two email addresses and prefer to be
      contacted with one of them.

      The value MUST be in the range of 1 to 100.  Lower values
      correspond to a higher level of preference, with 1 being most
      preferred.  If no preference is set, then the contact information
      MUST be interpreted as being least preferred.

      Note that the preference is only defined in relation to contact
      information of the same type.  For example, the preference orders
      within emails and phone numbers are independent of each other.

1.5.4.  phonetic

   The following properties define how to pronounce a value in the
   language indicated in the Card language (Section 2.1.5) property or
   the language tag of its localizations (Section 2.7.1).  Exemplary
   uses of these properties are defining how to pronounce Japanese names
   and romanizing Mandarin or Cantonese name and address components.
   The properties are defined as follows:

   phonetic: String.  The phonetic representation of a value.  Any
      script language subtag in the Card language (Section 2.1.5)
      property MUST be ignored and not used with the phonetic property.
      If this property is set, then at least one of the phoneticScript
      or phoneticSystem properties that relate to this value MUST be
      set.

   phoneticScript: String.  The script used in the value of the related
      phonetic property.  This MUST be a valid script subtag as defined
      in Section 2.2.3 of [RFC5646].

   phoneticSystem: String.  The phonetic system used in the related
      value of the phonetic property.  The enumerated (Section 1.7.5)
      values are:

      *  ipa: denotes the International Phonetic Alphabet [IPA].

      *  jyut: denotes the Cantonese romanization system "Jyutping".

      *  piny: denotes the Standard Mandarin romanization system "Hanyu
         Pinyin".

   The relation between the phoneticSystem, phoneticScript, and phonetic
   properties is type-specific.  This specification defines this
   relation in the Name (Section 2.2.1.1) and Address (Section 2.5.1.1)
   object types, respectively.

   The following example illustrates the phonetic property for a name
   (Section 2.2.1):

   "name": {
     "components": [{
       "kind": "given",
       "value": "John",
       "phonetic": "/ˈdʒɑːn/"
     }, {
       "kind": "surname",
       "value": "Smith",
       "phonetic": "/smɪθ/"
     }],
     "phoneticSystem": "ipa"
   }

   Figure 1: Example of a phonetic Property for the Name "John Smith" as
                           Pronounced in the USA

1.6.  Internationalization

   JSContact aims to be used for international contacts and address book
   data.  Notably, text values such as names and addresses are likely to
   cover a wide range of languages and cultures.  This section describes
   internationalization for free-form text values as well as Uniform
   Resource Identifiers (URIs).

1.6.1.  Free-Form Text

   Properties having free-form text values MAY contain any valid
   sequence of Unicode characters encoded as a JSON string.  Such values
   can contain unidirectional left-to-right and right-to-left text, as
   well as bidirectional text using Unicode Directional Formatting
   Characters as described in Section 2 of [UBiDi].  Implementations
   setting bidirectional text MUST make sure that each property value
   complies with the requirements of the Unicode Bidirectional
   Algorithm.  Implementations MUST NOT assume that text values of
   adjacent properties are processed or displayed as a combined string;
   for example, the values of a given name component and a surname
   component may or may not be rendered together.

1.6.2.  URIs

   Several properties require their string value to be a URI as defined
   in [RFC3986].  Implementations MUST make sure to use proper percent-
   encoding for URIs that cannot be represented using unreserved URI
   characters.  Section 3.1 of [RFC3987] defines how to convert
   Internationalized Resource Identifiers to URIs.  JSContact makes no
   recommendation on how to display URIs, but the WHATWG URL Living
   Standard (see "Internationalization and special characters"
   (Section 4.8.3) of [WHATWG-URL]) provides guidance for URLs found in
   the context of a web browser.

1.7.  Validating JSContact

   This specification distinguishes between three kinds of properties
   regarding validation: IANA-registered properties and unknown
   properties, which are defined in this section, and vendor-specific
   properties, which are defined in Section 1.8.1.  A JSContact object
   is invalid if any of its properties are invalid.

   This document defines whether each property is mandatory or optional.
   A mandatory property MUST be present for a JSContact object to be
   valid.  An optional property does not need to be present.  The values
   of both required and optional properties MUST adhere to the data type
   and definition of that property.

1.7.1.  Case-Sensitivity

   All property names, object type names, and enumerated values are
   case-sensitive, unless explicitly stated otherwise in their
   definitions.  Implementations MUST handle a JSContact object as
   invalid if a type name, property name, or enumerated value only
   differs in case from one defined for any JSContact version known to
   that implementation.  This applies regardless of what JSContact
   version the Card object defines in its version (Section 2.1.2)
   property.  Section 1.7.4 defines how to handle unknown properties.

1.7.2.  IANA-Registered Properties

   An IANA-registered property is any property that has been registered
   according to the IANA property registry rules as outlined in
   Section 3.  All properties defined in this specification, including
   their object value types and enumerated values, are registered at
   IANA.

   Implementations MUST validate IANA-registered properties in JSContact
   data, unless they are unknown to the implementation (Section 1.7.4).
   They MUST reject invalid IANA-registered properties.  A property is
   invalid if its name matches the name of an IANA-registered property
   but the value violates its definition according to the JSContact
   specification version defined in the Card version (Section 2.1.2)
   property.

   IANA-registered property names MUST NOT contain ASCII control
   characters (U+0000 to U+001F, U+007F), the COLON (U+003A), or the
   QUOTATION MARK (U+0022).  They MUST only contain ASCII alphanumeric
   characters that match the ALPHA and DIGIT rules defined in
   Appendix B.1 of [RFC5234] or the COMMERCIAL AT (U+0040) character.
   IANA-registered property names MUST be notated in lower camel case.

1.7.3.  Reserved Properties

   IANA-registered properties can be reserved (Section 3.3).
   Implementations MUST NOT set properties having a reserved name in
   JSContact objects for which this property is reserved or all objects
   if the property context in the registry is "not applicable".
   Reserved properties have no type, and their type signature is "not
   applicable".  Any JSContact object including a property that is
   reserved in context of this object MUST be considered invalid.

   This document reserves one property as described below.

1.7.3.1.  extra

   extra: not applicable.  The reserved property "extra" provides
      implementors with a property name that is certain to never occur
      as a property in any JSContact object.  Implementations might want
      to map unknown or vendor-specific properties to a variable with
      this name, but this is implementation-specific.

1.7.4.  Unknown Properties

   Implementations may encounter JSContact data where a property name is
   unknown to that implementation but the name adheres to the syntactic
   restrictions of IANA-registered property names.  Implementations MUST
   make sure that such a name does not violate the case-sensitivity
   rules defined in Section 1.7.1.  If the property name is valid, then
   implementations MUST NOT treat such properties as invalid.  Instead,
   they MUST preserve them in the JSContact object.

   Implementations that create or update JSContact data MUST only set
   IANA-registered properties or vendor-specific properties.  Preserving
   properties that are unknown to the implementation is to allow
   applications and services to interoperate without data loss, even if
   not all of them implement the same set of JSContact extensions.

1.7.5.  Enumerated Values

   Several properties in this document restrict their allowed values to
   a list of String values.  These values are case-sensitive.  If not
   noted otherwise for a specific property, the initial list of values
   for such properties is registered at IANA in the "JSContact Enum
   Values" registry (Section 3.7).  Implementations MUST only set IANA-
   registered or vendor-specific (Section 1.8.2) values for such
   properties.

1.8.  Vendor-Specific Extensions

   Vendors may extend properties and values for experimentation or to
   store contacts data that is only useful for a single service or
   application.  Such extensions are not meant for interoperation.  If,
   instead, interoperation is desired, vendors are strongly encouraged
   to define and register new properties, types, and values at IANA as
   defined in Section 3.  Section 1.7.2 defines the naming conventions
   for IANA-registered elements.

1.8.1.  Vendor-Specific Properties

   Vendor-specific property names MUST start with a vendor-specific
   prefix followed by a name, as produced by the "v-extension" ABNF
   below.  The prefix and name together form the property name.  The
   vendor-specific prefix MUST be a domain name under control of the
   service or application that sets the property, but it need not
   resolve in the Domain Name System [RFC1034] [RFC1035].  The prefix
   "ietf.org" and its subdomain names are reserved for IETF
   specifications.  The name MUST NOT contain the TILDE (U+007E) and
   SOLIDUS (U+002F) characters, as these require special escaping when
   encoding a JSON Pointer [RFC6901] for that property.

   Vendor-specific properties MAY be set in any JSContact object.
   Implementations MUST preserve vendor-specific properties in JSContact
   data, irrespective if they know their use.  They MUST NOT reject the
   property value as invalid, unless they are in control of the vendor-
   specific property as outlined in the above paragraph.

   The ABNF rule "v-extension" formally defines valid vendor-specific
   property names.  Note that the vendor prefix allows for more values
   than Internationalized Domain Names (IDNs) [RFC9499]; therefore,
   JSContact implementations can simply validate property names without
   implementing the full set of rules that apply to domain names.

   v-extension = v-prefix ":" v-name

   v-prefix = v-label *("." v-label)

   v-label = alnum-int / alnum-int *(alnum-int / "-") alnum-int

   alnum-int = ALPHA / DIGIT / NON-ASCII
     ; see RFC 6350, Section 3.3

   v-name = 1*(WSP / "!" / %x23-2e / %x30-7d / NON-ASCII)
     ; any characters except CTLs, DQUOTE, SOLIDUS, and TILDE

          Figure 2: ABNF Rules for Vendor-Specific Property Names

   The value of vendor-specific properties can be any valid JSON value,
   and naming restrictions do not apply to such values.  Specifically,
   if the property value is a JSON object, then the keys of such objects
   need not be named as vendor-specific properties, as illustrated in
   Figure 3:

   "example.com:foo": "bar",
   "example.com:foo2": {
     "bar": "baz"
   }

              Figure 3: Examples of Vendor-Specific Properties

1.8.2.  Vendor-Specific Values

   Some JSContact IANA-registered properties allow their values to be
   vendor-specific.  One such example is the "kind" (Section 2.1.4)
   property, which enumerates its standard values but also allows for
   arbitrary vendor-specific values.  Such vendor-specific values MUST
   be valid "v-extension" values as defined in Section 1.8.1.  The
   example in Figure 4 illustrates this:

   "kind": "example.com:baz"

                Figure 4: Example of a Vendor-Specific Value

   Vendors are strongly encouraged to specify a new standard value once
   a vendor-specific one turns out to also be useful for other systems.

1.9.  Versioning

   Every instance of a JSContact Card (Section 2) indicates which
   JSContact version its IANA-registered properties and values are based
   on.  The version is indicated both in the version (Section 2.1.2)
   property within the Card and in the version (Section 3.1) parameter
   of the JSContact media type.  All IANA-registered elements indicate
   the version at which they were introduced or obsoleted.

   A JSContact version consists of a major and minor version.

   Differing major version values indicate substantial differences in
   JSContact semantics and format.  Implementations MUST be prepared for
   property definitions and other JSContact elements that differ in a
   backwards-incompatible manner.

   Differing minor version values indicate additions that enrich
   JSContact data but do not introduce backwards-incompatible changes.
   Typically, these are new property enum values or properties with a
   narrow semantic scope.  A new minor version MUST NOT require
   implementations to change their processing of JSContact data.
   Changing the major version number resets the minor version number to
   zero.

1.9.1.  Version Format and Requirements

   A version value starts with the numeric major version, followed by
   the FULL STOP character (U+002E), followed by the numeric minor
   version.  Later versions are numerically higher than former versions,
   with the major version being more significant than the minor version.
   A version value is produced by the following ABNF:

   jsversion = 1*DIGIT "." 1*DIGIT

              Figure 5: The ABNF for JSContact Version Values

1.9.2.  Current Version

   This specification registers JSContact version value "1.0" (Table 1).

2.  Card

   This section defines the JSContact object type Card.  A Card stores
   contact information, typically that of a person, organization, or
   company.

   Its media type is defined in Section 3.1.

   Figure 6 shows a basic Card for the person "John Doe".  As the object
   is the topmost object in the JSON data, it has the @type property set
   according to the rules defined in Section 1.3.4.

   {
     "@type": "Card",
     "version": "1.0",
     "uid": "22B2C7DF-9120-4969-8460-05956FE6B065",
     "kind": "individual",
     "name": {
       "components": [
         { "kind": "given", "value": "John" },
         { "kind": "surname", "value": "Doe" }
       ],
       "isOrdered": true
     }
   }

                     Figure 6: Example of a Basic Card

2.1.  Metadata Properties

   This section defines properties about this instance of a Card such as
   its unique identifier, its creation date, and how it relates to other
   Cards and other metadata information.

2.1.1.  @type

   @type: String (mandatory).  The JSContact type of the Card object.
      The value MUST be "Card".

2.1.2.  version

   version: String (mandatory).  The JSContact version of this Card.
      The value MUST be one of the IANA-registered JSContact Version
      values for the version property.  Also see Section 1.9.2.

   "version": "1.0"

                 Figure 7: Example for the version Property

2.1.3.  created

   created: UTCDateTime (optional).  The date and time when the Card was
      created.

   "created": "2022-09-30T14:35:10Z"

                 Figure 8: Example for the created Property

2.1.4.  kind

   kind: String (optional; default: "individual").  The kind of the
      entity the Card represents.

      The enumerated (Section 1.7.5) values are:

      *  individual: a single person

      *  group: a group of people or entities

      *  org: an organization

      *  location: a named location

      *  device: a device such as an appliance, a computer, or a network
         element

      *  application: a software application

   "kind": "individual"

                  Figure 9: Example for the kind Property

2.1.5.  language

   language: String (optional).  The language tag, as defined in
      [RFC5646], that best describes the language used for text in the
      Card, optionally including additional information such as the
      script.  Note that values MAY be localized in the localizations
      (Section 2.7.1) property.

   "language": "de-AT"

                Figure 10: Example for the language Property

2.1.6.  members

   members: String[Boolean] (optional).  The set of Cards that are
      members of this group Card.  Each key in the set is the uid
      property value of the member, and each boolean value MUST be
      "true".  If this property is set, then the value of the kind
      property MUST be "group".

      The opposite is not true.  A group Card will usually contain the
      members property to specify the members of the group, but it is
      not required to.  A group Card without the members property can be
      considered an abstract grouping or one whose members are known
      empirically (e.g., "IETF Participants").

   "kind": "group",
   "name": {
     "full": "The Doe family"
   },
   "uid": "urn:uuid:ab4310aa-fa43-11e9-8f0b-362b9e155667",
   "members": {
     "urn:uuid:03a0e51f-d1aa-4385-8a53-e29025acd8af": true,
     "urn:uuid:b8767877-b4a1-4c70-9acc-505d3819e519": true
   }

                Figure 11: Example for the members Property

2.1.7.  prodId

   prodId: String (optional).  The identifier for the product that
      created the Card.  If set, the value MUST be at least one
      character long.

   "prodId": "ACME Contacts App version 1.23.5"

                 Figure 12: Example for the prodId Property

2.1.8.  relatedTo

   relatedTo: String[Relation] (optional).  The set of Card objects that
      relate to the Card.  The value is a map, where each key is the uid
      property value of the related Card, and the value defines the
      relation.

   The Relation object has the following properties:

   @type: String.
      The JSContact type of the object.  The value MUST be "Relation",
      if set.

   relation: String[Boolean] (optional; default: empty Object).
      The relationship of the related Card to the Card, defined as a set
      of relation types.  The keys in the set define the relation type;
      the values for each key in the set MUST be "true".  The
      relationship between the two objects is undefined if the set is
      empty.

      The initial list of enumerated (Section 1.7.5) relation types
      matches the IANA-registered TYPE [IANA-vCard] parameter values of
      the vCard RELATED property (Section 6.6.6 of [RFC6350]):

      *  acquaintance

      *  agent

      *  child

      *  co-resident

      *  co-worker

      *  colleague

      *  contact

      *  crush

      *  date

      *  emergency

      *  friend

      *  kin

      *  me

      *  met

      *  muse

      *  neighbor

      *  parent

      *  sibling

      *  spouse

      *  sweetheart

   "relatedTo": {
     "urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6": {
       "relation": {
         "friend": true
       }
     },
     "8cacdfb7d1ffdb59@example.com": {
       "relation": {}
     }
   }

               Figure 13: Example for the relatedTo Property

2.1.9.  uid

   uid: String (mandatory).  An identifier that associates the object as
      the same across different systems, address books, and views.  The
      value SHOULD be a URN [RFC8141], but for compatibility with
      [RFC6350], it MAY also be a URI [RFC3986] or free-text value.  The
      value of the URN SHOULD be in the "uuid" namespace [RFC9562].
      [RFC9562] describes multiple versions of Universally Unique
      IDentifiers (UUIDs); UUID version 4 is RECOMMENDED.

   "uid": "urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6"

                  Figure 14: Example for the uid Property

2.1.10.  updated

   updated: UTCDateTime (optional).  The date and time when the data in
      the Card was last modified.

   "updated": "2021-10-31T22:27:10Z"

                Figure 15: Example for the updated Property

2.2.  Name and Organization Properties

   This section defines properties that name the entity represented by
   the Card and its related organizations and roles.  It also describes
   how to refer to the entity represented by the Card in spoken or
   written language.

2.2.1.  name

   name: Name (optional).  The name of the entity represented by the
      Card.  This can be any type of name, e.g., it can, but need not,
      be the legal name of a person.

2.2.1.1.  Name Object

   A Name object has the following properties:

   @type: String.  The JSContact type of the object.  The value MUST be
      "Name", if set.

   components: NameComponent[] (optional).  The components
      (Section 2.2.1.2) making up this name.  The components property
      MUST be set if the full property is not set; otherwise, it SHOULD
      be set.  The component list MUST have at least one entry having a
      different kind property value than "separator".

      Name components SHOULD be ordered such that when their values are
      joined as a String, a valid full name of the entity is produced.
      If so, implementations MUST set the isOrdered property value to
      "true".

      If the name components are ordered, then the defaultSeparator
      property and name components with the kind property value set to
      "separator" give guidance on what characters to insert between
      components, but implementations are free to choose any others.
      When lacking a separator, inserting a single space character in
      between the name component values is a good choice.

      If, instead, the name components follow no particular order, then
      the isOrdered property value MUST be "false", the components
      property MUST NOT contain a NameComponent with the kind property
      value set to "separator", and the defaultSeparator property MUST
      NOT be set.

      Figure 16 shows an example for the name "Vincent van Gogh".  Note
      how a single name component value may consist of multiple words.

      "name": {
        "components": [
          { "kind": "given", "value": "Vincent" },
          { "kind": "surname", "value": "van Gogh" }
        ],
        "isOrdered": true
      }

                Figure 16: Example of a Surname with Two Words

      Figure 17 illustrates a name with a second surname such as a
      Spanish name.  Additional examples are shown in Figures 19 and 39.

      "name": {
        "components": [
          { "kind": "given", "value": "Diego" },
          { "kind": "surname", "value": "Rivera" },
          { "kind": "surname2", "value": "Barrientos" }
        ],
        "isOrdered": true
      }

                    Figure 17: Example of a Second Surname

   isOrdered: Boolean (optional; default: "false").  The indicator if
      the name components in the components property are ordered.

   defaultSeparator: String (optional).  The default separator to insert
      between name component values when concatenating all name
      component values to a single String.  Also see the definition of
      the kind property value "separator" for the NameComponent
      (Section 2.2.1.2) object.  The defaultSeparator property MUST NOT
      be set if the Name isOrdered property value is "false" or if the
      components property is not set.

   full: String (optional).  The full name representation of the Name.
      The full property MUST be set if the components property is not
      set.

      "full": "Mr. John Q. Public, Esq."

                   Figure 18: Example for the full Property

   sortAs: String[String] (optional).  The value to lexicographically
      sort the name in relation to other names when compared by a name
      component type.  The keys in the map define the name component
      type.  The values define the verbatim string to compare when
      sorting by the name component type.  Absence of a key indicates
      that the name component type SHOULD NOT be considered during sort.
      Sorting by that missing name component type, or if the sortAs
      property is not set, is implementation-specific.  The sortAs
      property MUST NOT be set if the components property is not set.

      Each key in the map MUST be a valid name component type value as
      defined for the kind property of the NameComponent object (see
      below).  For each key in the map, there MUST exist at least one
      NameComponent object that has the type in the components property
      of the name.

      Figure 19 illustrates the use of the sortAs property.  The
      property value indicates that the middle name followed by both
      surnames should be used when sorting the name by surname.  The
      absence of "middle" indicates that the middle name on its own
      should be disregarded during sort.  Even though the name only
      contains one name component for the given name, the sortAs
      property still explicitly defines how to sort by the given name;
      otherwise, sorting by it would be undefined.

   phoneticScript: String (optional).  The script used in the value of
      the NameComponent phonetic property.  See Section 1.5.4 for more
      information and Figure 20 for an example.

   phoneticSystem: String (optional).  The phonetic system used in the
      NameComponent phonetic property.  See Section 1.5.4 for more
      information and Figure 20 for an example.

   "name": {
     "components": [
       { "kind": "given", "value": "Robert" },
       { "kind": "given2", "value": "Pau" },
       { "kind": "surname", "value": "Shou Chang" }
     ],
     "sortAs": {
       "surname": "Pau Shou Chang",
       "given": "Robert"
     },
     "isOrdered": true
   }

                 Figure 19: Example for the sortAs Property

   {
     "@type": "Card",
     "language": "zh-Hant",
     "name": {
       "components": [
         { "kind": "surname", "value": "孫" },
         { "kind": "given", "value": "中山" },
         { "kind": "given2", "value": "文" },
         { "kind": "given2", "value": "逸仙" }
       ]
     },
     "localizations": {
       "yue": {
         "name/phoneticSystem": "jyut",
         "name/phoneticScript": "Latn",
         "name/components/0/phonetic": "syun1",
         "name/components/1/phonetic": "zung1saan1",
         "name/components/2/phonetic": "man4",
         "name/components/3/phonetic": "jat6sin1"
       }
     }
   }

      Figure 20: Example for the phonetic and localizations Properties

2.2.1.2.  NameComponent

   A NameComponent object has the following properties:

   @type: String.  The JSContact type of the object.  The value MUST be
      "NameComponent", if set.

   value: String (mandatory).  The value of the name component.  This
      can be composed of one or multiple words such as "Poe" or "van
      Gogh".

   kind: String (mandatory).  The kind of the name component.  The
      enumerated (Section 1.7.5) values are:

      *  title: an honorific title or prefix, e.g., "Mr.", "Ms.", or
         "Dr.".

      *  given: a given name, also known as "first name" or "personal
         name".

      *  given2: a name that appears between the given and surname such
         as a middle name or patronymic name.

      *  surname: a surname, also known as "last name" or "family name".

      *  surname2: a secondary surname (used in some cultures), also
         known as "maternal surname".

      *  credential: a credential, also known as "accreditation
         qualifier" or "honorific suffix", e.g., "B.A.", "Esq.".

      *  generation: a generation marker or qualifier, e.g., "Jr." or
         "III".

      *  separator: a formatting separator between two ordered name non-
         separator components.  The value property of the component
         includes the verbatim separator, for example, a hyphen
         character or even an empty string.  This value has higher
         precedence than the defaultSeparator property of the Name.
         Implementations MUST NOT insert two consecutive separator
         components; instead, they SHOULD insert a single separator
         component with the combined value.  This component kind MUST
         NOT be set if the Name isOrdered property value is "false".

   phonetic: String (optional).  The pronunciation of the name
      component.  If this property is set, then at least one of the Name
      object properties, phoneticSystem or phoneticScript, MUST be set.
      Also see Section 1.5.4.

2.2.2.  nicknames

   nicknames: Id[Nickname] (optional).  The nicknames of the entity
      represented by the Card.

   A Nickname object has the following properties:

   @type: String.  The JSContact type of the object.  The value MUST be
      "Nickname", if set.

   name: String (mandatory).  The nickname.

   contexts: String[Boolean] (optional).  The contexts in which to use
      the nickname.  Also see Section 1.5.1.

   pref: UnsignedInt (optional).  The preference of the nickname in
      relation to other nicknames.  Also see Section 1.5.3.

   "nicknames": {
     "k391": {
       "name": "Johnny"
     }
   }

               Figure 21: Example for the nicknames Property

2.2.3.  organizations

   organizations: Id[Organization] (optional).  The company or
      organization names and units associated with the Card.

   An Organization object has the following properties, of which at
   least one of the name and units properties MUST be set:

   @type: String.  The JSContact type of the object.  The value MUST be
      "Organization", if set.

   name: String (optional).  The name of the organization.

   units: OrgUnit[] (optional).  A list of organizational units, ordered
      as descending by hierarchy (e.g., a geographic or functional
      division sorts before a department within that division).  If set,
      the list MUST contain at least one entry.

   sortAs: String (optional).  The value to lexicographically sort the
      organization in relation to other organizations when compared by
      name.  The value defines the verbatim string value to compare.  In
      absence of this property, the name property value MAY be used for
      comparison.

   contexts: String[Boolean] (optional).  The contexts in which
      association with the organization applies.  For example,
      membership in a choir may only apply in a private context.  Also
      see Section 1.5.1.

   An OrgUnit object has the following properties:

   @type: String.  The JSContact type of the object.  The value MUST be
      "OrgUnit", if set.

   name: String (mandatory).  The name of the organizational unit.

   sortAs: String (optional).  The value to lexicographically sort the
      organizational unit in relation to other organizational units of
      the same level when compared by name.  The level is defined by the
      array index of the organizational unit in the units property of
      the Organization object.  The property value defines the verbatim
      string value to compare.  In absence of this property, the name
      property value MAY be used for comparison.

   "organizations": {
     "o1": {
       "name": "ABC, Inc.",
       "units": [
         { "name": "North American Division" },
         { "name": "Marketing" }
       ],
       "sortAs": "ABC"
     }
   }

             Figure 22: Example for the organizations Property

2.2.4.  speakToAs

   speakToAs: SpeakToAs (optional).  The information that directs how to
      address, speak to, or refer to the entity that is represented by
      the Card.

   A SpeakToAs object has the following properties, of which at least
   one of the grammaticalGender and pronouns properties MUST be set:

   @type: String.  The JSContact type of the object.  The value MUST be
      "SpeakToAs", if set.

   grammaticalGender: String (optional).  The grammatical gender to use
      in salutations and other grammatical constructs.  For example, the
      German language distinguishes by grammatical gender in salutations
      such as "Sehr geehrte" (feminine) and "Sehr geehrter" (masculine).
      The enumerated (Section 1.7.5) values are:

      *  animate
      *  common
      *  feminine
      *  inanimate
      *  masculine
      *  neuter

      Note that the grammatical gender does not allow inferring the
      gender identities or assigned sex of the contact.

   pronouns: Id[Pronouns] (optional).  The pronouns that the contact
      chooses to use for themselves.

   A Pronouns object has the following properties:

   @type: String.  The JSContact type of the object.  The value MUST be
      "Pronouns", if set.

   pronouns: String (mandatory).  The pronouns.  Any value or form is
      allowed.  Examples in English include "she/her" and "they/them/
      theirs".  The value MAY be overridden in the localizations
      (Section 2.7.1) property.

   contexts: String[Boolean] (optional).  The contexts in which to use
      the pronouns.  Also see Section 1.5.1.

   pref: UnsignedInt (optional).  The preference of the pronouns in
      relation to other pronouns in the same context.  Also see
      Section 1.5.3.

   "speakToAs": {
     "grammaticalGender": "neuter",
     "pronouns": {
       "k19": {
         "pronouns": "they/them",
         "pref": 2
       },
       "k32": {
         "pronouns": "xe/xir",
         "pref": 1
       }
     }
   }

               Figure 23: Example for the speakToAs Property

2.2.5.  titles

   titles: Id[Title] (optional).  The job titles or functional positions
      of the entity represented by the Card.

   A Title object has the following properties:

   @type: String.  The JSContact type of the object.  The value MUST be
      "Title", if set.

   name: String (mandatory).  The title or role name of the entity
      represented by the Card.

   kind: String (optional; default: "title").  The organizational or
      situational kind of the title.  Some organizations and individuals
      distinguish between _titles_ as organizational positions and
      _roles_ as more temporary assignments such as in project
      management.

      The enumerated (Section 1.7.5) values are:

      *  title
      *  role

   organizationId: Id (optional).  The identifier of the organization in
      which this title is held.

   "titles": {
     "le9": {
       "kind": "title",
       "name": "Research Scientist"
     },
     "k2": {
       "kind": "role",
       "name": "Project Leader",
       "organizationId": "o2"
     }
   },
   "organizations": {
     "o2": {
       "name": "ABC, Inc."
     }
   }

                 Figure 24: Example for the titles Property

2.3.  Contact Properties

   This section defines how properties contact the entity represented by
   the Card.

2.3.1.  emails

   emails: Id[EmailAddress] (optional).  The email addresses in which to
      contact the entity represented by the Card.

   An EmailAddress object has the following properties:

   @type: String.  The JSContact type of the object.  The value MUST be
      "EmailAddress", if set.

   address: String (mandatory).  The email address.  This MUST be an
      _addr-spec_ value as defined in Section 3.4.1 of [RFC5322].

   contexts: String[Boolean] (optional).  The contexts in which to use
      this email address.  Also see Section 1.5.1.

   pref: UnsignedInt (optional).  The preference of the email address in
      relation to other email addresses.  Also see Section 1.5.3.

   label: String (optional).  A custom label for the value.  Also see
      Section 1.5.2.

   "emails": {
     "e1": {
       "contexts": {
         "work": true
       },
       "address": "jqpublic@xyz.example.com"
     },
     "e2": {
       "address": "jane_doe@example.com",
       "pref": 1
     }
   }

                 Figure 25: Example for the emails Property

2.3.2.  onlineServices

   onlineServices: Id[OnlineService] (optional).  The online services
      that are associated with the entity represented by the Card.  This
      can be messaging services, social media profiles, and other.

   An OnlineService object has the following properties, of which at
   least the uri or user property MUST be set:

   @type: String.  The JSContact type of the object.  The value MUST be
      "OnlineService", if set.

   service: String (optional).  The name of the online service or
      protocol.  The name MAY be capitalized the same as on the
      service's website, app, or publishing material, but names MUST be
      considered equal if they match case-insensitively.  Examples are
      "GitHub", "kakao", and "Mastodon".

   uri: String (optional).  The identifier for the entity represented by
      the Card at the online service.  This MUST be a _URI_ as defined
      in Section 3 of [RFC3986].

   user: String (optional).  The name the entity represented by the Card
      at the online service.  Any free-text value is allowed.  The
      service property SHOULD be set.

   contexts: String[Boolean] (optional).  The contexts in which to use
      the service.  Also see Section 1.5.1.

   pref: UnsignedInt (optional).  The preference of the service in
      relation to other services.  Also see Section 1.5.3.

   label: String (optional).  A custom label for the value.  Also see
      Section 1.5.2.

   "onlineServices": {
     "x1": {
       "uri": "xmpp:alice@example.com"
     },
     "x2": {
       "service": "Mastodon",
       "user": "@alice@example2.com",
       "uri": "https://example2.com/@alice"
     }
   }

             Figure 26: Example for the onlineServices Property

2.3.3.  phones

   phones: Id[Phone] (optional).  The phone numbers by which to contact
      the entity represented by the Card.

   Phone object has the following properties:

   @type: String.  The JSContact type of the object.  The value MUST be
      "Phone", if set.

   number: String (mandatory).  The phone number as either a URI or free
      text.  Typical URI schemes are "tel" [RFC3966] or "sip" [RFC3261],
      but any URI scheme is allowed.

   features: String[Boolean] (optional).  The set of contact features
      that the phone number may be used for.  The set is represented as
      an object, with each key being a method type.  The boolean value
      MUST be "true".  The enumerated (Section 1.7.5) method type values
      are:

      *  mobile: this number is for a mobile phone.
      *  voice: this number supports calling by voice.
      *  text: this number supports text messages (SMS).
      *  video: this number supports video conferencing.
      *  main-number: this number is a main phone number such as the
         number of the front desk at a company, as opposed to a direct-
         dial number of an individual employee.
      *  textphone: this number is for a device for people with hearing
         or speech difficulties.
      *  fax: this number supports sending faxes.
      *  pager: this number is for a pager or beeper.

   contexts: String[Boolean] (optional).  The contexts in which to use
      the number.  Also see Section 1.5.1.

   pref: UnsignedInt (optional).  The preference of the number in
      relation to other numbers.  Also see Section 1.5.3.

   label: String (optional).  A custom label for the value.  Also see
      Section 1.5.2.

   "phones": {
     "tel0": {
       "contexts": {
         "private": true
       },
       "features": {
         "voice": true
       },
       "number": "tel:+1-555-555-5555;ext=5555",
       "pref": 1
     },
     "tel3": {
       "contexts": {
         "work": true
       },
       "number": "tel:+1-201-555-0123"
     }
   }

                 Figure 27: Example for the phones Property

2.3.4.  preferredLanguages

   preferredLanguages : Id[LanguagePref] (optional).  The preferred
      languages for contacting the entity associated with the Card.

   A LanguagePref object has the following properties:

   @type: String.  The JSContact type of the object.  The value MUST be
      "LanguagePref", if set.

   language: String (mandatory).  The preferred language.  This MUST be
      a language tag as defined in [RFC5646] .

   contexts: String[Boolean] (optional).  The contexts in which to use
      the language.  Also see Section 1.5.1.

   pref: UnsignedInt (optional).  The preference of the language in
      relation to other languages of the same contexts.  Also see
      Section 1.5.3.

   "preferredLanguages": {
     "l1": {
       "language": "en",
       "contexts": {
         "work": true
       },
       "pref": 1
     },
     "l2": {
       "language": "fr",
       "contexts": {
         "work": true
       },
       "pref": 2
     },
     "l3": {
       "language": "fr",
       "contexts": {
         "private": true
       }
     }
   }

           Figure 28: Example for the preferredLanguages Property

2.4.  Calendaring and Scheduling Properties

   This section defines properties for scheduling calendar events with
   the entity represented by the Card.

2.4.1.  calendars

   calendars: Id[Calendar] (optional).  The calendaring resources of the
      entity represented by the Card, such as to look up free-busy
      information.

   A Calendar object has all properties of the Resource (Section 1.4.4)
   data type, with the following additional definitions:

   *  The @type property value MUST be "Calendar", if set.

   *  The kind property is mandatory.  Its enumerated (Section 1.7.5)
      values are:

      -  calendar: The resource is a calendar that contains entries such
         as calendar events or tasks.

      -  freeBusy: The resource allows for free-busy lookups, for
         example, to schedule group events.

   "calendars": {
     "calA": {
       "kind": "calendar",
       "uri": "webcal://calendar.example.com/calA.ics"
     },
     "project-a": {
       "kind": "freeBusy",
       "uri": "https://calendar.example.com/busy/project-a"
     }
   }

               Figure 29: Example for the calendars Property

2.4.2.  schedulingAddresses

   schedulingAddresses: Id[SchedulingAddress] (optional).  The
      scheduling addresses by which the entity may receive calendar
      scheduling invitations.

   A SchedulingAddress object has the following properties:

   @type: String.  The JSContact type of the object.  The value MUST be
      "SchedulingAddress", if set.

   uri: String (mandatory).  The address to use for calendar scheduling
      with the contact.  This MUST be a URI as defined in Section 3 of
      [RFC3986].

   contexts: String[Boolean] (optional).  The contexts in which to use
      the scheduling address.  Also see Section 1.5.1.

   pref: UnsignedInt (optional).  The preference of the scheduling
      address in relation to other scheduling addresses.  Also see
      Section 1.5.3.

   label: String (optional).  A custom label for the scheduling address.
      Also see Section 1.5.2.

   "schedulingAddresses": {
     "sched1": {
       "uri": "mailto:janedoe@example.com"
     }
   }

          Figure 30: Example for the schedulingAddresses Property

2.5.  Address and Location Properties

   This section defines properties for postal addresses and geographical
   locations associated with the entity represented by the Card.

2.5.1.  addresses

   addresses: Id[Address] (optional).  The addresses of the entity
      represented by the Card, such as postal addresses or geographic
      locations.

2.5.1.1.  Address Object

   An Address object has the following properties, of which at least one
   of components, coordinates, countryCode, full or timeZone MUST be
   set:

   @type: String.  The JSContact type of the object.  The value MUST be
      "Address", if set.

   components: AddressComponent[] (optional).  The components
      (Section 2.5.1.2) that make up the address.  The component list
      MUST have at least one entry that has a kind property value other
      than "separator".

      Address components SHOULD be ordered such that when their values
      are joined as a String, a valid full address is produced.  If so,
      implementations MUST set the isOrdered property value to "true".

      If the address components are ordered, then the defaultSeparator
      property and address components with the kind property value set
      to "separator" give guidance on what characters to insert between
      components, but implementations are free to choose any others.
      When lacking a separator, inserting a single space character in
      between address component values is a good choice.

      If, instead, the address components follow no particular order,
      then the isOrdered property value MUST be "false", the components
      property MUST NOT contain an AddressComponent with the kind
      property value set to "separator", and the defaultSeparator
      property MUST NOT be set.

   isOrdered: Boolean (optional; default: "false").  The indicator if
      the address components in the components property are ordered.

   countryCode: String (optional).  The Alpha-2 country code
      [ISO.3166-1].

   coordinates: String (optional).  A "geo:" URI [RFC5870] for the
      address.

   timeZone: String (optional).  The time zone in which the address is
      located.  This MUST be a time zone name registered in the IANA
      Time Zone Database [IANA-TZ].

   contexts: String[Boolean] (optional).  The contexts in which to use
      this address.  The boolean value MUST be "true".  In addition to
      the common contexts (Section 1.5.1), allowed key values are:

      *  billing: an address to be used for billing.
      *  delivery: an address to be used for delivering physical items.

   full: String (optional).  The full address, including street, region,
      or country.  The purpose of this property is to define an address,
      even if the individual address components are not known.

   defaultSeparator: String (optional).  The default separator to insert
      between address component values when concatenating all address
      component values to a single String.  Also see the definition of
      the kind property value "separator" for the AddressComponent
      (Section 2.5.1.2) object.  The defaultSeparator property MUST NOT
      be set if the Address isOrdered property value is "false" or if
      the components property is not set.

   pref: UnsignedInt (optional).  The preference of the address in
      relation to other addresses.  Also see Section 1.5.3.

   phoneticScript: String (optional).  The script used in the value of
      the AddressComponent phonetic property.  Also see Section 1.5.4.

   phoneticSystem: String (optional).  The phonetic system used in the
      AddressComponent phonetic property.  Also see Section 1.5.4.

   The following example illustrates the use of the address property for
   "54321 Oak St, Reston, CA 20190, USA".  Additional examples are shown
   in Section 2.5.1.3.

   "addresses": {
     "k23": {
       "contexts": {
         "work": true
       },
       "components": [
         { "kind": "number", "value": "54321" },
         { "kind": "separator", "value": " " },
         { "kind": "name", "value": "Oak St" },
         { "kind": "locality", "value": "Reston" },
         { "kind": "region", "value": "VA" },
         { "kind": "separator", "value": " " },
         { "kind": "postcode", "value": "20190" },
         { "kind": "country", "value": "USA" }
       ],
       "countryCode": "US",
       "defaultSeparator": ", ",
       "isOrdered": true
     }
   }

                Figure 31: Example of an Address in the USA

2.5.1.2.  AddressComponent Object

   An AddressComponent object has the following properties:

   @type: String.  The JSContact type of the object.  The value MUST be
      "AddressComponent", if set.

   value: String (mandatory).  The value of the address component.

   kind: String (mandatory).  The kind of the address component.  The
      enumerated (Section 1.7.5) values are:

      *  room: the room, suite number, or identifier.
      *  apartment: the extension designation such as the apartment
         number, unit, or box number.
      *  floor: the floor or level the address is located on.
      *  building: the building, tower, or condominium the address is
         located in.
      *  number: the street number, e.g., "123".  This value is not
         restricted to numeric values and can include any value such as
         number ranges ("112-10"), grid style ("39.2 RD"), alphanumerics
         ("N6W23001"), or fractionals ("123 1/2").
      *  name: the street name.
      *  block: the block name or number.
      *  subdistrict: the subdistrict, ward, or other subunit of a
         district.
      *  district: the district name.
      *  locality: the municipality, city, town, village, post town, or
         other locality.
      *  region: the administrative area such as province, state,
         prefecture, county, or canton.
      *  postcode: the postal code, post code, ZIP code, or other short
         code associated with the address by the relevant country's
         postal system.
      *  country: the country name.
      *  direction: the cardinal direction or quadrant, e.g., "north".
      *  landmark: the publicly known prominent feature that can
         substitute the street name and number, e.g., "White House" or
         "Taj Mahal".
      *  postOfficeBox: the post office box number or identifier.
      *  separator: a formatting separator between two ordered address
         non-separator components.  The value property of the component
         includes the verbatim separator, for example, a hyphen
         character or even an empty string.  This value has higher
         precedence than the defaultSeparator property of the Address.
         Implementations MUST NOT insert two consecutive separator
         components; instead, they SHOULD insert a single separator
         component with the combined value.  This component kind MUST
         NOT be set if the Address isOrdered property value is "false".

   phonetic: String (optional).  The pronunciation of the name
      component.  If this property is set, then at least one of the
      Address object phoneticSystem or phoneticScript properties MUST be
      set.  Also see Section 1.5.4.

2.5.1.3.  Additional Address Examples

   The following example illustrates the use of the address property for
   "46, 1 Sukhumvit 51 Alley, Khlong Tan Nuea, Watthana, Bangkok 10110,
   Thailand".

   "addresses": {
     "k25": {
       "components": [
         { "kind": "number", "value": "46" },
         { "kind": "name", "value": "1 Sukhumvit 51 Alley" },
         { "kind": "subdistrict", "value": "Khlong Tan Nuea" },
         { "kind": "district", "value": " Watthana" },
         { "kind": "locality", "value": "Bangkok" },
         { "kind": "country", "value": "Thailand" },
         { "kind": "postcode", "value": "10110" }
       ],
       "defaultSeparator": ", ",
       "isOrdered": true
     }
   }

                Figure 32: Example of an Address in Thailand

   The following example illustrates the use of the address property for
   "2-7-2 Marunouchi, Chiyoda-ku, Tokyo 100-8994" and its Japanese
   localization (Section 2.7.1).

   "addresses": {
      "k26": {
        "components": [
          { "kind": "block", "value": "2-7" },
          { "kind": "separator", "value": "-" },
          { "kind": "number", "value": "2" },
          { "kind": "separator", "value": " " },
          { "kind": "district", "value": "Marunouchi" },
          { "kind": "locality", "value": "Chiyoda-ku" },
          { "kind": "region", "value": "Tokyo" },
          { "kind": "separator", "value": " " },
          { "kind": "postcode", "value": "100-8994" }
        ],
        "defaultSeparator": ", ",
        "full": "2-7-2 Marunouchi, Chiyoda-ku, Tokyo 100-8994",
        "isOrdered": true
      }
   },
   "localizations": {
     "jp": {
       "addresses/k26": {
         "components": [
           { "kind": "region", "value": "東京都" },
           { "kind": "locality", "value": "千代田区" },
           { "kind": "district", "value": "丸ノ内" },
           { "kind": "block", "value": "2-7" },
           { "kind": "separator", "value": "-" },
           { "kind": "number", "value": "2" },
           { "kind": "postcode", "value": "〒100-8994" }
         ],
         "defaultSeparator": "",
         "full": "〒100-8994東京都千代田区丸ノ内2-7-2",
         "isOrdered": true
       }
     }
   }

     Figure 33: Example of an Address in Tokyo and Its Localization in
                                  Japanese

2.6.  Resource Properties

   This section defines properties for digital resources associated with
   the entity represented by the Card.

2.6.1.  cryptoKeys

   cryptoKeys: Id[CryptoKey] (optional).  The cryptographic resources
      such as public keys and certificates associated with the entity
      represented by the Card.

   A CryptoKey object has all properties of the Resource (Section 1.4.4)
   data type, with the following additional definition:

   *  The @type property value MUST be "CryptoKey", if set.

   The following example shows how to refer to an external cryptographic
   resource.

   "cryptoKeys": {
     "mykey1": {
       "uri": "https://www.example.com/keys/jdoe.cer"
     }
   }

            Figure 34: Example of cryptoKeys with External Data

   The following example shows how to embed key data in the CryptoKey.
   The key data is depicted in multiple lines only for demonstration
   purposes.

   "cryptoKeys": {
     "mykey2": {
       "uri": "data:application/pgp-keys;base64,LS0tLS1CRUdJTiBSU0EgUFVC
               TElDIEtFWS0tLS0tCk1JSUJDZ0tDQVFFQSt4R1ovd2N6OXVnRnBQMDdOc
               3BvNlUxN2wwWWhGaUZweHhVNHBUazNMaWZ6OVIzenNJc3UKRVJ3dGE3K2
               ZXSWZ4T28yMDhldHQvamhza2lWb2RTRXQzUUJHaDRYQmlweVdvcEt3Wjk
               zSEhhRFZaQUFMaS8yQQoreFRCdFdkRW83WEdVdWpLRHZDMi9hWkt1a2Zq
               cE9pVUk4QWhMQWZqbWxjRC9VWjFRUGgwbUhzZ2xSTkNtcEN3Cm13U1hBO
               VZObWh6K1BpQitEbWw0V1duS1cvVkhvMnVqVFh4cTcrZWZNVTRIMmZueT
               NTZTNLWU9zRlBGR1oxVE4KUVNZbEZ1U2hXckhQdGlMbVVkUG9QNkNWMm1
               NTDF0aytsN0RJSXFYclFoTFVLREFDZU01cm9NeDBrTGhVV0I4UAorMHVq
               MUNObE5ONEpSWmxDN3hGZnFpTWJGUlU5WjRONll3SURBUUFCCi0tLS0tR
               U5EIFJTQSBQVUJMSUMgS0VZLS0tLS0K"
     }
   }

            Figure 35: Example of cryptoKeys with Embedded Data

2.6.2.  directories

   directories: Id[Directory] (optional).  The directories containing
      information about the entity represented by the Card.

   A Directory object has all properties of the Resource (Section 1.4.4)
   data type, with the following additional definitions:

   *  The @type property value MUST be "Directory", if set.

   *  The kind property is mandatory.  Its enumerated (Section 1.7.5)
      values are:

      -  directory: the resource is a directory service that the entity
         represented by the Card is a part of.  This typically is an
         organizational directory that also contains associated
         entities, e.g., co-workers and management in a company
         directory.

      -  entry: the resource is a directory entry of the entity
         represented by the Card.  In contrast to the "directory" type,
         this is the specific URI for the entity _within_ a directory.

   In addition, the Directory object has the following property:

   listAs: UnsignedInt (optional).  The position of the directory
      resource in the list of all Directory objects having the same kind
      property value in the Card.  If set, the listAs value MUST be
      higher than zero.  Multiple directory resources MAY have the same
      listAs property value or none.  Sorting such same-valued entries
      is implementation-specific.

   "directories": {
     "dir1": {
       "kind": "entry",
       "uri": "https://dir.example.com/addrbook/jdoe/Jean%20Dupont.vcf"
     },
     "dir2": {
       "kind": "directory",
       "uri": "ldap://ldap.example/o=Example%20Tech,ou=Engineering",
       "pref": 1
     }

              Figure 36: Example for the directories Property

2.6.3.  links

   links: Id[Link] (optional).  The links to resources that do not fit
      any of the other use-case-specific resource properties.

   A Link object has all properties of the Resource (Section 1.4.4) data
   type, with the following additional definitions:

   *  The @type property value MUST be "Link", if set.

   *  The kind property is optional.  Its enumerated (Section 1.7.5)
      values are:

      -  contact: the resource is a URI by which the entity represented
         by the Card may be contacted; this includes web forms or other
         media that require user interaction.

   "links": {
     "link3": {
       "kind": "contact",
       "uri": "mailto:contact@example.com",
       "pref": 1
     }
   }

                 Figure 37: Example for the links Property

2.6.4.  media

   media: Id[Media] (optional).  The media resources such as
      photographs, avatars, or sounds that are associated with the
      entity represented by the Card.

   A Media object has all properties of the Resource (Section 1.4.4)
   data type, with the following additional definitions:

   *  The @type property value MUST be "Media", if set.

   *  The kind property is mandatory.  Its enumerated (Section 1.7.5)
      values are:

      -  photo: the resource is a photograph or avatar.

      -  sound: the resource is audio media, e.g., to specify the proper
         pronunciation of the name property contents.

      -  logo: the resource is a graphic image or logo associated with
         the entity represented by the Card.

   "media": {
     "res45": {
       "kind": "sound",
       "uri": "CID:JOHNQ.part8.19960229T080000.xyzMail@example.com"
     },
     "res47": {
       "kind": "logo",
       "uri": "https://www.example.com/pub/logos/abccorp.jpg"
     },
     "res1": {
       "kind": "photo",
       "uri": "data:image/jpeg;base64,/9j/4AAQSkZJRgABAQAASABIAAD/4..."
     }
   }

                 Figure 38: Example for the media Property

2.7.  Multilingual Properties

   This section defines properties for localizing the content of the
   Card in human languages.

2.7.1.  localizations

   localizations: String[PatchObject] (optional).  The property values
      localized to languages other than the main language
      (Section 2.1.5) of the Card.  Localizations provide language-
      specific alternatives for existing property values and SHOULD NOT
      add new properties.  The keys in the localizations property value
      are language tags [RFC5646]; the values are of type PatchObject
      and localize the Card in that language tag.  The paths in the
      PatchObject are relative to the Card that includes the
      localizations property.  A patch MUST NOT target the localizations
      property.

   Conceptually, a Card is localized as follows:

   *  Determine the language tag in which the Card should be localized.

   *  If the localizations property includes a key for that language,
      obtain the PatchObject value.  If there is no such key, stop.

   *  Create a copy of the Card, but do not copy the localizations
      property.

   *  Apply all patches in the PatchObject to the copy of the Card.

   *  Optionally, set the language property in the copy of the Card.

   *  Use the patched copy of the Card as the localized variant of the
      original Card.

   A patch in the PatchObject may contain any value type.  Its value
   MUST be a valid value according to the definition of the patched
   property.

   Figure 39 localizes the name property by completely replacing its
   contents in Ukrainian language with Cyrillic script.

   {
     "name": {
       "components": [
         { "kind": "title", "value": "Mr." },
         { "kind": "given", "value": "Ivan" },
         { "kind": "given2", "value": "Petrovich" },
         { "kind": "surname", "value": "Vasiliev" }
       ]
     },
     "localizations": {
       "uk-Cyrl": {
         "name": {
           "components": [
             { "kind": "title", "value": "г-н" },
             { "kind": "given", "value": "Иван" },
             { "kind": "given2", "value": "Петрович" },
             { "kind": "surname", "value": "Васильев" }
           ]
         }
       }
     }
   }

           Figure 39: Example of Localizing a Top-Level Property

   Figure 40 localizes the title name by patching _inside_ the titles
   property.  All properties, except the name property in the Title
   object, are left as is.

   "name": {
     "full": "Gabriel García Márquez"
   },
   "titles": {
     "t1": {
       "kind": "title",
       "name": "novelist"
     }
   },
   "localizations": {
     "es": {
       "titles/t1/name": "escritor"
     }
   }

             Figure 40: Example of Localizing a Nested Property

2.8.  Additional Properties

   This section defines properties for which none of the previous
   sections are appropriate.

2.8.1.  anniversaries

   anniversaries: Id[Anniversary] (optional).  The memorable dates and
      events for the entity represented by the Card.

   An Anniversary object has the following properties:

   @type: String.  The JSContact type of the object.  The value MUST be
      "Anniversary", if set.

   kind: String (mandatory).  The kind of anniversary.  The enumerated
      (Section 1.7.5) values are:

      *  birth: a birthday anniversary
      *  death: a deathday anniversary
      *  wedding: a wedding day anniversary

   date: PartialDate|Timestamp (mandatory; defaultType: PartialDate).  T
      he date of the anniversary in the Gregorian calendar.  This MUST
      be either a whole or partial calendar date or a complete UTC
      timestamp (see the definition of the Timestamp and PartialDate
      object types below).

   place: Address (optional).  An address associated with this
      anniversary, e.g., the place of birth or death.

   A PartialDate object represents a complete or partial calendar date
   in the Gregorian calendar.  It represents a complete date, a year, a
   month in a year, or a day in a month.  It has the following
   properties:

   @type: String.  The JSContact type of the object.  The value MUST be
      "PartialDate", if set.

   year:  UnsignedInt (optional).  The calendar year.

   month: UnsignedInt (optional).  The calendar month, represented as
      the integers 1 <= month <= 12.  If this property is set, then
      either the year or the day property MUST be set.

   day: UnsignedInt (optional).  The calendar month day, represented as
      the integers 1 <= day <= 31, depending on the validity within the
      month and year.  If this property is set, then the month property
      MUST be set.

   calendarScale: String (optional).  The calendar system in which this
      date occurs, in lowercase.  This MUST be either a calendar system
      name registered as a Common Locale Data Repository (CLDR)
      [RFC7529] or a vendor-specific value.  The year, month, and day
      still MUST be represented in the Gregorian calendar.  Note that
      the year property might be required to convert the date between
      the Gregorian calendar and the respective calendar system.

   A Timestamp object has the following properties:

   @type: String.  The JSContact type of the object.  The value MUST be
      "Timestamp", if set.

   utc: UTCDateTime (mandatory).  The point in time in UTC time.

   Figure 41 illustrates anniversaries with partial dates and a
   timestamp.  Note how the @type property is set for the Timestamp
   object value according to the rules defined in Section 1.3.4.

   "anniversaries": {
     "k8": {
       "kind": "birth",
       "date": {
         "year": 1953,
         "month": 4,
         "day": 15
       }
     },
     "k9": {
       "kind": "death",
       "date": {
         "@type": "Timestamp",
         "utc": "2019-10-15T23:10:00Z"
       },
       "place": {
         "full": "4445 Tree Street\nNew England, ND 58647\nUSA"
       }
     }
   }

             Figure 41: Example for the anniversaries Property

2.8.2.  keywords

   keywords: String[Boolean] (optional).  The set of free-text keywords,
      also known as _tags_. Each key in the set is a keyword, and each
      boolean value MUST be "true".

   "keywords": {
     "internet": true,
     "IETF": true
   }

                Figure 42: Example for the keywords Property

2.8.3.  notes

   notes: Id[Note] (optional).  The free-text notes that are associated
      with the Card.

   A Note object has the following properties:

   @type: String.  The JSContact type of the object.  The value MUST be
      "Note", if set.

   note: String (mandatory).  The free-text value of this note.

   created: UTCDateTime (optional).  The date and time when this note
      was created.

   author: Author (optional).  The author of this note.

   An Author object has the following properties, of which at least one
   property other than @type MUST be set:

   @type: String.  The JSContact type of the object.  The value MUST be
      "Author", if set.

   name: String (optional).  The name of this author.

   uri: String (optional).  The URI value that identifies the author.

   "notes": {
     "n1": {
       "note": "Open office hours are 1600 to 1715 EST, Mon-Fri",
       "created": "2022-11-23T15:01:32Z",
       "author": {
         "name": "John"
       }
     }
   }

                 Figure 43: Example for the notes Property

2.8.4.  personalInfo

   personalInfo: Id[PersonalInfo] (optional).  The personal information
      of the entity represented by the Card.

   A PersonalInfo object has the following properties:

   @type: String.  The JSContact type of the object.  The value MUST be
      "PersonalInfo", if set.

   kind: String (mandatory).  The kind of personal information.  The
      enumerated (Section 1.7.5) values are:

      *  expertise: a field of expertise or a credential

      *  hobby: a hobby

      *  interest: an interest

   value: String (mandatory).  The actual information.

   level: String (optional).  The level of expertise or engagement in
      hobby or interest.  The enumerated (Section 1.7.5) values are:

      *  high

      *  medium

      *  low

   listAs: UnsignedInt (optional).  The position of the personal
      information in the list of all PersonalInfo objects that have the
      same kind property value in the Card.  If set, the listAs value
      MUST be higher than zero.  Multiple personal information entries
      MAY have the same listAs property value or none.  Sorting such
      same-valued entries is implementation-specific.

   label: String (optional).  A custom label.  See Section 1.5.2.

   "personalInfo": {
     "pi2": {
       "kind": "expertise",
       "value": "chemistry",
       "level": "high"
     },
     "pi1": {
       "kind": "hobby",
       "value": "reading",
       "level": "high"
     },
     "pi6": {
       "kind": "interest",
       "value": "r&b music",
       "level": "medium"
     }
   }

              Figure 44: Example for the personalInfo Property

3.  IANA Considerations

3.1.  Media Type Registration

   This document defines a media type for use with JSContact data
   formatted in JSON.

   Type name:  application

   Subtype name:  jscontact+json

   Required parameters:  None

   Optional parameters:  version

      This parameter conveys the version of the JSContact data in the
      body part.  It MUST NOT occur more than once.  If this parameter
      is set, then the values of all JSContact version (Table 2)
      properties in the body part MUST match the parameter value.

   Encoding considerations:  This is the same as the encoding
      considerations of application/json, as specified in Section 11 of
      [RFC8259].

   Security considerations:  See Section 4 of RFC 9553.

   Interoperability considerations:  While JSContact is designed to
      avoid ambiguities as much as possible, when converting objects
      from other contact formats to/from JSContact, it is possible that
      differing representations for the same logical data or ambiguities
      in interpretation might arise.  The semantic equivalence of two
      JSContact objects may be determined differently by different
      applications, for example, where URL values differ in case between
      the two objects.

   Published specification:  RFC 9553

   Applications that use this media type:  Applications that currently
      make use of the text/vcard media type can use this as an
      alternative.

   Fragment identifier considerations:  A JSON Pointer fragment
      identifier may be used, as defined in [RFC6901], Section 6.

   Additional information:

      Magic number(s):  N/A
      File extensions(s):  N/A
      Macintosh file type code(s):  N/A

   Person & email address to contact for further information:
      calsify@ietf.org

   Intended usage:  COMMON

   Restrictions on usage:  N/A

   Author:  See the "Authors' Addresses" section of RFC 9553.

   Change controller:  IETF

3.2.  Creation of the JSContact Registry Group

   IANA has created the "JSContact" registry group.  The new registry
   definitions in the following sections all belong to that group.

3.3.  Registry Policy and Change Procedures

   Registry assignments that introduce backwards-incompatible
   (Section 1.9) changes require the JSContact major version to change;
   other changes only require a change to the minor version.  The
   registry policy for assignments that require the JSContact major
   version to change is Standards Action ([RFC8126], Section 4.9).  The
   registry policy for other assignments is Specification Required
   ([RFC8126], Section 4.6).

   The designated expert (DE) decides if a major or minor version change
   is required and assigns the new version to the "JSContact Version"
   registry (Section 3.4).  Version numbers increment by one, and a
   major version change resets the minor version to zero.  An assignment
   may apply multiple changes and to more than one registry at once, in
   which case a single version change is sufficient.  If the registry
   policy is Specification Required, then the DE may decide that it is
   enough to document the new assignment in the Description item of the
   respective registry.

   A registration MUST have an intended usage of "common", "reserved",
   or "obsolete".

   *  A "common" usage denotes an item with shared semantics and syntax
      across systems.  Up-to-date systems MUST expect such items to
      occur in JSContact data.

   *  A "reserved" usage reserves an item in the registry without
      assigning semantics to avoid name collisions with future
      extensions or protocol use.  Implementations MUST NOT expect or
      add items with such names outside the protocols or extensions that
      use them; otherwise, any such JSContact data is invalid.

   *  An "obsolete" usage denotes an item that is no longer expected to
      be added by up-to-date systems.  A new assignment has probably
      been defined, covering the obsolete item's semantics.
      Implementations MUST expect such items to occur in JSContact data
      up to the "Until Version" registry field, inclusively.  They MUST
      NOT add such items for any version after which the item was
      obsoleted; otherwise, any such JSContact data is invalid.

   The intended usage of registry items may change between versions, but
   the DE must carefully consider the impact on existing implementations
   and standards before doing so.

   The registration procedure is not a formal standards process but
   rather an administrative procedure intended to allow community
   comments and to check whether it is coherent without excessive time
   delay.  It is designed to encourage vendors to document and register
   new items they add for use cases not covered by the original
   specification, leading to increased interoperability.

3.3.1.  Preliminary Community Review

   Notice of a potential new registration MUST be sent to the Calext WG
   mailing list <calsify@ietf.org> for review.  This mailing list is
   appropriate for soliciting community feedback on a proposed registry
   assignment.

   The intent of the public posting to this list is to solicit comments
   and feedback on the choice of the item name or value, the unambiguity
   of its description, and a review of any interoperability or security
   considerations.  The submitter may submit a revised registration
   proposal or abandon the registration completely at any time.

3.3.2.  Submit Request to IANA

   Registration requests can be sent to IANA <iana@iana.org>.

3.3.3.  Designated Expert Review

   The primary concern of the DE is preventing name collisions and
   encouraging the submitter to document security and privacy
   considerations.

   A new type name, property name, or enumerated value MUST NOT differ
   only in case from an already-registered name or value.

   For a common-use registration, the DE is expected to confirm that
   suitable documentation is available to ensure interoperability.  The
   DE should also verify that the new assignment does not conflict with
   work that is active or already published within the IETF.

   The DE will either approve or deny the registration request and
   publish a notice of the decision to the Calext WG mailing list or its
   successor, as well as inform IANA.  A denial notice must be justified
   by an explanation, and in the cases where it is possible, concrete
   suggestions on how the request can be modified to become acceptable
   should be provided.

3.3.4.  Change Procedures

   Once a JSContact registry group item has been published by IANA, the
   Change Controller may request a change to its definition.  The same
   procedure that would be appropriate for the original registration
   request is used to process a change request.

   JSContact registrations do not get deleted; instead, items that are
   no longer believed appropriate for use are declared obsolete by a
   change to their "Intended Usage" field; such items will be clearly
   marked in the IANA registry.

   Significant changes to a JSContact registry item's definition should
   be requested only when there are serious omissions or errors in the
   published specification, as such changes may cause interoperability
   issues.  When review is required, a change request may be denied if
   it renders entities that were valid under the previous definition
   invalid under the new definition.

3.4.  Creation of the JSContact Version Registry

   IANA has created the "JSContact Version" registry.  The purpose of
   this new registry is to define the allowed value range of JSContact
   major and minor version numbers.

   The registry entries sort numerically in ascending order by the
   "Major Version" column, and entries with equal "Major Version" sort
   numerically in ascending order by the "Minor Version" column.

   The registry process is outlined in Section 3.3.

3.4.1.  JSContact Version Registry Template

   Major Version:  The numeric value of a JSContact major version
      number.  It MUST be a positive integer.

   Highest Minor Version:  The maximum numeric value of a JSContact
      minor version for the given major version.  It MUST be zero or a
      positive integer.  All numbers less than or equal to this value
      are valid minor version values for the given major version.

3.4.2.  Initial Contents of the JSContact Version Registry

   The following table lists the initial valid major and minor version
   number ranges.

           +===============+=======================+===========+
           | Major Version | Highest Minor Version | Reference |
           +===============+=======================+===========+
           | 1             | 0                     | RFC 9553  |
           +---------------+-----------------------+-----------+

                    Table 1: JSContact Version Registry

3.5.  Creation of the JSContact Properties Registry

   IANA has created the "JSContact Properties" registry.  The purpose of
   this new registry is to allow interoperability of extensions to
   JSContact objects.

   The registry entries sort alphabetically in ascending order by the
   following columns: "Property Name" first, "Property Context" second,
   and "Since Version" third.  Equal entries sort in any order.

   The registry process for a new property is outlined in Section 3.3.

3.5.1.  JSContact Properties Registry Template

   Property Name:  The name of the property.  The property name MUST NOT
      already be registered for any of the object types listed in the
      "Property Context" field of this registration.  Other object types
      MAY have already registered a different property with the same
      name; however, the same name MUST only be used when the semantics
      are analogous.

   Property Type:  For properties with intended usage other than
      "reserved", this is the type of this property, using type
      signatures as specified in Section 1.3.2.  The property type MUST
      be registered in the "JSContact Types" registry.  For reserved
      property names, the value MUST be the verbatim string "not
      applicable".

   Property Context:  A comma-separated list of JSContact object types
      (Section 3.6.2) that contain the property.  For reserved property
      names, the value MAY be the verbatim string "not applicable".

   Intended Usage:  May be "common", "reserved", or "obsolete".

   Since Version:  The JSContact version on which the property
      definition is based.  The version MUST be one of the allowed
      values of the version property in the "JSContact Version" registry
      (see Table 1).

   Until Version:  The JSContact version after which the property was
      obsoleted; therefore, it MUST NOT be used in later versions.  The
      Until Version value either MUST NOT be set or MUST be one of the
      allowed values of the version property in the "JSContact Version"
      registry (see Table 1).

   Change Controller:  Person or entity responsible for requesting a
      change to the entry's definition ("IETF" for RFCs from the IETF
      stream).

   Reference or Description:  A brief description or RFC number and
      section reference where the property is specified.  This must
      include references to all RFC documents where this property is
      introduced or updated.  For reserved property names, the reference
      or description MAY be omitted.

3.5.2.  Initial Contents of the JSContact Properties Registry

   The following table lists the initial "common" usage entries of the
   "JSContact Properties" registry.  For all properties, the Since
   Version is "1.0", the Until Version is not set, the Change Controller
   is "IETF", and RFC section references are for RFC 9553.

   +=====================+=======================+====================+
   | Property Name       | Property Type         | Property Context   |
   +=====================+=======================+====================+
   | @type               | String                | Address            |
   |                     |                       | (Section 2.5.1.1), |
   |                     |                       | AddressComponent   |
   |                     |                       | (Section 2.5.1.2), |
   |                     |                       | Anniversary        |
   |                     |                       | (Section 2.8.1),   |
   |                     |                       | Author             |
   |                     |                       | (Section 2.8.3),   |
   |                     |                       | Card               |
   |                     |                       | (Section 2.1.1),   |
   |                     |                       | Calendar           |
   |                     |                       | (Section 2.4.1),   |
   |                     |                       | CryptoKey          |
   |                     |                       | (Section 2.6.1),   |
   |                     |                       | Directory          |
   |                     |                       | (Section 2.6.2),   |
   |                     |                       | EmailAddress       |
   |                     |                       | (Section 2.3.1),   |
   |                     |                       | LanguagePref       |
   |                     |                       | (Section 2.3.4),   |
   |                     |                       | Link               |
   |                     |                       | Section 2.6.3),    |
   |                     |                       | Media              |
   |                     |                       | (Section 2.6.4),   |
   |                     |                       | Name               |
   |                     |                       | (Section 2.2.1.1), |
   |                     |                       | NameComponent      |
   |                     |                       | (Section 2.2.1.2), |
   |                     |                       | Nickname           |
   |                     |                       | (Section 2.2.2),   |
   |                     |                       | Note               |
   |                     |                       | (Section 2.8.3),   |
   |                     |                       | OnlineService      |
   |                     |                       | (Section 2.3.2),   |
   |                     |                       | Organization       |
   |                     |                       | (Section 2.2.3),   |
   |                     |                       | OrgUnit            |
   |                     |                       | (Section 2.2.3),   |
   |                     |                       | PartialDate        |
   |                     |                       | (Section 2.8.1),   |
   |                     |                       | PersonalInfo       |
   |                     |                       | (Section 2.8.4),   |
   |                     |                       | Phone              |
   |                     |                       | (Section 2.3.3),   |
   |                     |                       | Pronouns           |
   |                     |                       | (Section 2.2.4),   |
   |                     |                       | Relation           |
   |                     |                       | (Section 2.1.8),   |
   |                     |                       | SchedulingAddress  |
   |                     |                       | (Section 2.4.2),   |
   |                     |                       | SpeakToAs          |
   |                     |                       | (Section 2.2.4),   |
   |                     |                       | Timestamp          |
   |                     |                       | (Section 2.8.1),   |
   |                     |                       | Title              |
   |                     |                       | (Section 2.2.5)    |
   +---------------------+-----------------------+--------------------+
   | address             | String                | EmailAddress       |
   |                     |                       | (Section 2.3.1)    |
   +---------------------+-----------------------+--------------------+
   | addresses           | Id[Address]           | Card               |
   |                     |                       | (Section 2.5.1.1)  |
   +---------------------+-----------------------+--------------------+
   | anniversaries       | Id[Anniversary]       | Card               |
   |                     |                       | (Section 2.8.1)    |
   +---------------------+-----------------------+--------------------+
   | author              | Author                | Note               |
   |                     |                       | (Section 2.8.3)    |
   +---------------------+-----------------------+--------------------+
   | calendars           | Id[Calendar]          | Card               |
   |                     |                       | (Section 2.4.1)    |
   +---------------------+-----------------------+--------------------+
   | calendarScale       | String                | PartialDate        |
   |                     |                       | (Section 2.8.1)    |
   +---------------------+-----------------------+--------------------+
   | components          | AddressComponent[]    | Address            |
   |                     |                       | (Section 2.5.1.1)  |
   +---------------------+-----------------------+--------------------+
   | components          | NameComponent[]       | Name               |
   |                     |                       | (Section 2.2.1.2)  |
   +---------------------+-----------------------+--------------------+
   | contexts            | String[Boolean]       | Address            |
   |                     |                       | (Section 2.5.1.1), |
   |                     |                       | Calendar           |
   |                     |                       | (Section 2.4.1),   |
   |                     |                       | CryptoKey          |
   |                     |                       | (Section 2.6.1),   |
   |                     |                       | Directory          |
   |                     |                       | (Section 2.6.2),   |
   |                     |                       | EmailAddress       |
   |                     |                       | (Section 2.3.1),   |
   |                     |                       | LanguagePref       |
   |                     |                       | (Section 2.3.4),   |
   |                     |                       | Link               |
   |                     |                       | (Section 2.6.3),   |
   |                     |                       | Media              |
   |                     |                       | (Section 2.6.4),   |
   |                     |                       | Nickname           |
   |                     |                       | (Section 2.2.2),   |
   |                     |                       | OnlineService      |
   |                     |                       | (Section 2.3.2),   |
   |                     |                       | Organization       |
   |                     |                       | (Section 2.2.3),   |
   |                     |                       | Phone              |
   |                     |                       | (Section 2.3.3),   |
   |                     |                       | Pronouns           |
   |                     |                       | (Section 2.2.4),   |
   |                     |                       | SchedulingAddress  |
   |                     |                       | (Section 2.4.2).   |
   |                     |                       | Also see Sections  |
   |                     |                       | 1.4.4 and 1.5.1.   |
   +---------------------+-----------------------+--------------------+
   | coordinates         | String                | Address            |
   |                     |                       | (Section 2.5.1.1)  |
   +---------------------+-----------------------+--------------------+
   | countryCode         | String                | Address            |
   |                     |                       | (Section 2.5.1.1)  |
   +---------------------+-----------------------+--------------------+
   | created             | UTCDateTime           | Card               |
   |                     |                       | (Section 2.1.3),   |
   |                     |                       | Note               |
   |                     |                       | (Section 2.8.3)    |
   +---------------------+-----------------------+--------------------+
   | date                | PartialDate|Timestamp | Anniversary        |
   |                     |                       | (Section 2.8.1)    |
   +---------------------+-----------------------+--------------------+
   | day                 | UnsignedInt           | PartialDate        |
   |                     |                       | (Section 2.8.1)    |
   +---------------------+-----------------------+--------------------+
   | defaultSeparator    | String                | Address            |
   |                     |                       | (Section 2.5.1.1), |
   |                     |                       | Name               |
   |                     |                       | (Section 2.2.1.1)  |
   +---------------------+-----------------------+--------------------+
   | directories         | Id[Directory]         | Card               |
   |                     |                       | (Section 2.6.2)    |
   +---------------------+-----------------------+--------------------+
   | emails              | Id[EmailAddress]      | Card               |
   |                     |                       | (Section 2.3.1)    |
   +---------------------+-----------------------+--------------------+
   | features            | String[Boolean]       | Phone              |
   |                     |                       | (Section 2.3.3)    |
   +---------------------+-----------------------+--------------------+
   | full                | String                | Address            |
   |                     |                       | (Section 2.5.1.1), |
   |                     |                       | Name               |
   |                     |                       | (Section 2.2.1.1)  |
   +---------------------+-----------------------+--------------------+
   | grammaticalGender   | String                | SpeakToAs          |
   |                     |                       | (Section 2.2.4)    |
   +---------------------+-----------------------+--------------------+
   | isOrdered           | Boolean               | Address            |
   |                     |                       | (Section 2.5.1.1), |
   |                     |                       | Name               |
   |                     |                       | (Section 2.2.1.1)  |
   +---------------------+-----------------------+--------------------+
   | keywords            | String[Boolean]       | Card               |
   |                     |                       | (Section 2.8.2)    |
   +---------------------+-----------------------+--------------------+
   | kind                | String                | AddressComponent   |
   |                     |                       | (Section 2.5.1.2), |
   |                     |                       | Anniversary        |
   |                     |                       | (Section 2.8.1),   |
   |                     |                       | Calendar           |
   |                     |                       | (Section 2.4.1),   |
   |                     |                       | Card               |
   |                     |                       | (Section 2.1.4),   |
   |                     |                       | CryptoKey          |
   |                     |                       | (Section 2.6.1),   |
   |                     |                       | Directory          |
   |                     |                       | (Section 2.6.2),   |
   |                     |                       | Link               |
   |                     |                       | (Section 2.6.3),   |
   |                     |                       | Media              |
   |                     |                       | (Section 2.6.4),   |
   |                     |                       | NameComponent      |
   |                     |                       | (Section 2.2.1.2), |
   |                     |                       | PersonalInfo       |
   |                     |                       | (Section 2.8.4),   |
   |                     |                       | Title              |
   |                     |                       | (Section 2.2.5)    |
   +---------------------+-----------------------+--------------------+
   | label               | String                | Calendar           |
   |                     |                       | (Section 2.4.1),   |
   |                     |                       | CryptoKey          |
   |                     |                       | (Section 2.6.1),   |
   |                     |                       | Directory          |
   |                     |                       | (Section 2.6.2),   |
   |                     |                       | EmailAddress       |
   |                     |                       | (Section 2.3.1),   |
   |                     |                       | Link               |
   |                     |                       | (Section 2.6.3),   |
   |                     |                       | Media              |
   |                     |                       | (Section 2.6.4),   |
   |                     |                       | OnlineService      |
   |                     |                       | (Section 2.3.2),   |
   |                     |                       | PersonalInfo       |
   |                     |                       | (Section 2.8.4),   |
   |                     |                       | Phone              |
   |                     |                       | (Section 2.3.3),   |
   |                     |                       | SchedulingAddress  |
   |                     |                       | (Section 2.4.2).   |
   |                     |                       | Also see Sections  |
   |                     |                       | 1.4.4 and 1.5.2.   |
   +---------------------+-----------------------+--------------------+
   | language            | String                | Card               |
   |                     |                       | (Section 2.1.5),   |
   |                     |                       | LanguagePref       |
   |                     |                       | (Section 2.3.4)    |
   +---------------------+-----------------------+--------------------+
   | level               | String                | PersonalInfo       |
   |                     |                       | (Section 2.8.4)    |
   +---------------------+-----------------------+--------------------+
   | links               | Id[Link]              | Card               |
   |                     |                       | (Section 2.6.3)    |
   +---------------------+-----------------------+--------------------+
   | listAs              | UnsignedInt           | Directory          |
   |                     |                       | (Section 2.6.2),   |
   |                     |                       | PersonalInfo       |
   |                     |                       | (Section 2.8.4)    |
   +---------------------+-----------------------+--------------------+
   | localizations       | String[PatchObject]   | Card               |
   |                     |                       | (Section 2.7.1)    |
   +---------------------+-----------------------+--------------------+
   | media               | Id[Media]             | Card               |
   |                     |                       | (Section 2.6.4)    |
   +---------------------+-----------------------+--------------------+
   | mediaType           | String                | Calendar           |
   |                     |                       | (Section 2.4.1),   |
   |                     |                       | CryptoKey          |
   |                     |                       | (Section 2.6.1),   |
   |                     |                       | Directory          |
   |                     |                       | (Section 2.6.2),   |
   |                     |                       | Link               |
   |                     |                       | (Section 2.6.3),   |
   |                     |                       | Media              |
   |                     |                       | (Section 2.6.4).   |
   |                     |                       | Also see           |
   |                     |                       | Section 1.4.4.     |
   +---------------------+-----------------------+--------------------+
   | members             | String[Boolean]       | Card               |
   |                     |                       | (Section 2.1.6)    |
   +---------------------+-----------------------+--------------------+
   | month               | UnsignedInt           | PartialDate        |
   |                     |                       | (Section 2.8.1)    |
   +---------------------+-----------------------+--------------------+
   | name                | Name                  | Card               |
   |                     |                       | (Section 2.2.1.1)  |
   +---------------------+-----------------------+--------------------+
   | name                | String                | Author             |
   |                     |                       | (Section 2.8.3),   |
   |                     |                       | Nickname           |
   |                     |                       | (Section 2.2.2),   |
   |                     |                       | Organization       |
   |                     |                       | (Section 2.2.3),   |
   |                     |                       | OrgUnit            |
   |                     |                       | (Section 2.2.3),   |
   |                     |                       | Title              |
   |                     |                       | (Section 2.2.5)    |
   +---------------------+-----------------------+--------------------+
   | nicknames           | Id[Nickname]          | Card               |
   |                     |                       | (Section 2.2.2)    |
   +---------------------+-----------------------+--------------------+
   | note                | String                | Note               |
   |                     |                       | (Section 2.8.3)    |
   +---------------------+-----------------------+--------------------+
   | notes               | Id[Note]              | Card               |
   |                     |                       | (Section 2.8.3)    |
   +---------------------+-----------------------+--------------------+
   | number              | String                | Phone              |
   |                     |                       | (Section 2.3.3)    |
   +---------------------+-----------------------+--------------------+
   | onlineServices      | Id[OnlineService]     | Card               |
   |                     |                       | (Section 2.3.2)    |
   +---------------------+-----------------------+--------------------+
   | organizationId      | String                | Title              |
   |                     |                       | (Section 2.2.5)    |
   +---------------------+-----------------------+--------------------+
   | organizations       | Id[Organization]      | Card               |
   |                     |                       | (Section 2.2.3)    |
   +---------------------+-----------------------+--------------------+
   | personalInfo        | Id[PersonalInfo]      | Card               |
   |                     |                       | (Section 2.8.4)    |
   +---------------------+-----------------------+--------------------+
   | phones              | Id[Phone]             | Card               |
   |                     |                       | (Section 2.3.3)    |
   +---------------------+-----------------------+--------------------+
   | phonetic            | String                | AddressComponent   |
   |                     |                       | (Section 2.5.1.2), |
   |                     |                       | NameComponent      |
   |                     |                       | (Section 2.2.1.2)  |
   +---------------------+-----------------------+--------------------+
   | phoneticScript      | String                | Address            |
   |                     |                       | (Section 2.5.1.1), |
   |                     |                       | Name               |
   |                     |                       | (Section 2.2.1.1)  |
   +---------------------+-----------------------+--------------------+
   | phoneticSystem      | String                | Address (2.5.1.1), |
   |                     |                       | Name               |
   |                     |                       | (Section 2.2.1.1)  |
   +---------------------+-----------------------+--------------------+
   | place               | Address               | Anniversary        |
   |                     |                       | (Section 2.8.1)    |
   +---------------------+-----------------------+--------------------+
   | pref                | UnsignedInt           | Address            |
   |                     |                       | (Section 2.5.1.1), |
   |                     |                       | Calendar           |
   |                     |                       | (Section 2.4.1),   |
   |                     |                       | CryptoKey          |
   |                     |                       | (Section 2.6.1),   |
   |                     |                       | Directory          |
   |                     |                       | (Section 2.6.2),   |
   |                     |                       | EmailAddress       |
   |                     |                       | (Section 2.3.1),   |
   |                     |                       | LanguagePref       |
   |                     |                       | (Section 2.3.4),   |
   |                     |                       | Link               |
   |                     |                       | (Section 2.6.3),   |
   |                     |                       | Media              |
   |                     |                       | (Section 2.6.4),   |
   |                     |                       | Nickname           |
   |                     |                       | (Section 2.2.2),   |
   |                     |                       | OnlineService      |
   |                     |                       | (Section 2.3.2),   |
   |                     |                       | Phone              |
   |                     |                       | (Section 2.3.3),   |
   |                     |                       | Pronouns           |
   |                     |                       | (Section 2.2.4),   |
   |                     |                       | SchedulingAddress  |
   |                     |                       | (Section 2.4.2).   |
   |                     |                       | Also see Sections  |
   |                     |                       | 1.4.4 and 1.5.3.   |
   +---------------------+-----------------------+--------------------+
   | preferredLanguages  | String[LanguagePref]  | Card               |
   |                     |                       | (Section 2.3.4)    |
   +---------------------+-----------------------+--------------------+
   | prodId              | String                | Card               |
   |                     |                       | (Section 2.1.7)    |
   +---------------------+-----------------------+--------------------+
   | pronouns            | Id[Pronouns]          | SpeakToAs          |
   |                     |                       | (Section 2.2.4)    |
   +---------------------+-----------------------+--------------------+
   | relatedTo           | String[Relation]      | Card               |
   |                     |                       | (Section 2.1.8)    |
   +---------------------+-----------------------+--------------------+
   | relation            | String[Boolean]       | Relation           |
   |                     |                       | (Section 2.1.8)    |
   +---------------------+-----------------------+--------------------+
   | schedulingAddresses | Id[SchedulingAddress] | Card               |
   |                     |                       | (Section 2.4.2)    |
   +---------------------+-----------------------+--------------------+
   | service             | String                | OnlineService      |
   |                     |                       | (Section 2.3.2)    |
   +---------------------+-----------------------+--------------------+
   | sortAs              | String[String]        | Name               |
   |                     |                       | (Section 2.2.1.1)  |
   +---------------------+-----------------------+--------------------+
   | sortAs              | String                | Organization       |
   |                     |                       | (Section 2.2.3),   |
   |                     |                       | OrgUnit            |
   |                     |                       | (Section 2.2.3)    |
   +---------------------+-----------------------+--------------------+
   | speakToAs           | SpeakToAs             | Card               |
   |                     |                       | (Section 2.2.4)    |
   +---------------------+-----------------------+--------------------+
   | timeZone            | String                | Address            |
   |                     |                       | (Section 2.5.1.1)  |
   +---------------------+-----------------------+--------------------+
   | titles              | Id[Title]             | Card               |
   |                     |                       | (Section 2.2.5)    |
   +---------------------+-----------------------+--------------------+
   | uid                 | String                | Card               |
   |                     |                       | (Section 2.1.9)    |
   +---------------------+-----------------------+--------------------+
   | units               | OrgUnit[]             | Organization       |
   |                     |                       | (Section 2.2.3)    |
   +---------------------+-----------------------+--------------------+
   | updated             | UTCDateTime           | Card               |
   |                     |                       | (Section 2.1.10)   |
   +---------------------+-----------------------+--------------------+
   | uri                 | String                | Author             |
   |                     |                       | (Section 2.8.3),   |
   |                     |                       | Calendar           |
   |                     |                       | (Section 2.4.1),   |
   |                     |                       | CryptoKey          |
   |                     |                       | (Section 2.6.1),   |
   |                     |                       | Directory          |
   |                     |                       | (Section 2.6.2),   |
   |                     |                       | Link               |
   |                     |                       | (Section 2.6.3),   |
   |                     |                       | Media              |
   |                     |                       | (Section 2.6.4),   |
   |                     |                       | OnlineService      |
   |                     |                       | (Section 2.3.2),   |
   |                     |                       | SchedulingAddress  |
   |                     |                       | (Section 2.4.2).   |
   |                     |                       | Also see           |
   |                     |                       | Section 1.4.4.     |
   +---------------------+-----------------------+--------------------+
   | user                | String                | OnlineService      |
   |                     |                       | (Section 2.3.2)    |
   +---------------------+-----------------------+--------------------+
   | utc                 | UTCDateTime           | Timestamp          |
   |                     |                       | (Section 2.8.1)    |
   +---------------------+-----------------------+--------------------+
   | value               | String                | AddressComponent   |
   |                     |                       | (Section 2.5.1.2), |
   |                     |                       | NameComponent      |
   |                     |                       | (Section 2.2.1.2), |
   |                     |                       | PersonalInfo       |
   |                     |                       | (Section 2.8.4)    |
   +---------------------+-----------------------+--------------------+
   | version             | String                | Card               |
   |                     |                       | (Section 2.1.2)    |
   +---------------------+-----------------------+--------------------+
   | year                | UnsignedInt           | PartialDate        |
   |                     |                       | (Section 2.8.1)    |
   +---------------------+-----------------------+--------------------+

            Table 2: JSContact Properties with "common" Usage

   The following table lists the initial "reserved" usage entries of the
   "JSContact Properties" registry.  For this property, the Change
   Controller is "IETF", and the RFC section reference is for RFC 9553.

   +===============+============+============+==========+=============+
   | Property Name | Property   | Property   | Intended | Reference/  |
   |               | Type       | Context    | Usage    | Description |
   +===============+============+============+==========+=============+
   | extra         | not        | not        | reserved | Section     |
   |               | applicable | applicable |          | 1.7.3.1     |
   +---------------+------------+------------+----------+-------------+

           Table 3: JSContact Properties with "reserved" Usage

3.6.  Creation of the JSContact Types Registry

   IANA has created the "JSContact Types" registry.  The purpose of this
   new registry is to avoid name collisions for JSContact type names and
   provide a complete reference for all data types used for JSContact
   property values.

   The registry entries sort alphabetically in ascending order by the
   "Type Name" column.  Equal entries sort in any order.

   The registry process for a new type is outlined in Section 3.3.

3.6.1.  JSContact Types Registry Template

   Type Name:  The name of the type.

   Intended Usage:  May be "common", "reserved", or "obsolete".

   Since Version:  The JSContact version on which this type definition
      is based.  The version MUST be one of the allowed values of the
      version property in the "JSContact Version" registry (see
      Table 1).

   Until Version:  The JSContact version after which the type definition
      was obsoleted; therefore, it MUST NOT be used in later versions.
      The Until Version value either MUST NOT be set or MUST be one of
      the allowed values of the version property in the "JSContact
      Version" registry (see Table 1).

   Change Controller:  Person or entity responsible for requesting a
      change to the entry's definition ("IETF" for RFCs from the IETF
      stream).

   Reference or Description:  A brief description or RFC number and
      section reference where the Type is specified.  For reserved type
      names, the reference or description MAY be omitted.

3.6.2.  Initial Contents of the JSContact Types Registry

   The following table lists the initial "common" usage entries in the
   "JSContact Types" registry.  For all of these types, the Since
   Version is "1.0", the Until Version is not set, the Change Controller
   is "IETF", and RFC section references are for RFC 9553.

   +===================+=======================+
   | Type Name         | Reference/Description |
   +===================+=======================+
   | Address           | Section 2.5.1.1       |
   +-------------------+-----------------------+
   | AddressComponent  | Section 2.5.1.2       |
   +-------------------+-----------------------+
   | Anniversary       | Section 2.8.1         |
   +-------------------+-----------------------+
   | Author            | Section 2.8.3         |
   +-------------------+-----------------------+
   | Boolean           | Section 1.3.2         |
   +-------------------+-----------------------+
   | Calendar          | Section 2.4.1         |
   +-------------------+-----------------------+
   | Card              | Section 2             |
   +-------------------+-----------------------+
   | CryptoKey         | Section 2.6.1         |
   +-------------------+-----------------------+
   | Directory         | Section 2.6.2         |
   +-------------------+-----------------------+
   | EmailAddress      | Section 2.3.1         |
   +-------------------+-----------------------+
   | Id                | Section 1.4.1         |
   +-------------------+-----------------------+
   | Int               | Section 1.4.2         |
   +-------------------+-----------------------+
   | LanguagePref      | Section 2.3.4         |
   +-------------------+-----------------------+
   | Link              | Section 2.6.3         |
   +-------------------+-----------------------+
   | Media             | Section 2.6.4         |
   +-------------------+-----------------------+
   | Name              | Section 2.2.1.1       |
   +-------------------+-----------------------+
   | NameComponent     | Section 2.2.1.2       |
   +-------------------+-----------------------+
   | Nickname          | Section 2.2.2         |
   +-------------------+-----------------------+
   | Note              | Section 2.8.3         |
   +-------------------+-----------------------+
   | Number            | Section 1.3.2         |
   +-------------------+-----------------------+
   | OnlineService     | Section 2.3.2         |
   +-------------------+-----------------------+
   | Organization      | Section 2.2.3         |
   +-------------------+-----------------------+
   | OrgUnit           | Section 2.2.3         |
   +-------------------+-----------------------+
   | PartialDate       | Section 2.8.1         |
   +-------------------+-----------------------+
   | PatchObject       | Section 1.4.3         |
   +-------------------+-----------------------+
   | PersonalInfo      | Section 2.8.4         |
   +-------------------+-----------------------+
   | Phone             | Section 2.3.3         |
   +-------------------+-----------------------+
   | Pronouns          | Section 2.2.4         |
   +-------------------+-----------------------+
   | Relation          | Section 2.1.8         |
   +-------------------+-----------------------+
   | SchedulingAddress | Section 2.4.2         |
   +-------------------+-----------------------+
   | SpeakToAs         | Section 2.2.4         |
   +-------------------+-----------------------+
   | String            | Section 1.3.2         |
   +-------------------+-----------------------+
   | Timestamp         | Section 2.8.1         |
   +-------------------+-----------------------+
   | Title             | Section 2.2.5         |
   +-------------------+-----------------------+
   | UnsignedInt       | Section 1.4.2         |
   +-------------------+-----------------------+
   | UTCDateTime       | Section 1.4.5         |
   +-------------------+-----------------------+

    Table 4: JSContact Types with "common" Usage

   The following table lists the initial "reserved" usage entry of the
   "JSContact Types" registry.  For this type, the version is "1.0", the
   Change Controller is "IETF", and the RFC section reference is for RFC
   9553.

   +===========+=======================+
   | Type Name | Reference/Description |
   +===========+=======================+
   | Resource  | Section 1.4.4         |
   +-----------+-----------------------+

       Table 5: JSContact Types with
              "reserved" Usage

3.7.  Creation of the JSContact Enum Values Registry

   IANA has created the "JSContact Enum Values" registry.  The purpose
   of the new registry is to allow interoperable extension of semantics
   for JSContact properties with enumerable values.  Each such property
   will have a subregistry of allowed values.

   The registry entries sort alphabetically in ascending order by the
   following columns: "Property Name" first, "Property Context" second,
   and "Since Version" third.  The enum values sort alphabetically in
   ascending order.  Equal entries sort in any order.

   The registry process for a new enum value or adding a new enumerable
   property is outlined in Section 3.3.

3.7.1.  JSContact Enum Values Registry Property Template

   This template is for adding a subregistry for a new enumerable
   property to the "JSContact Enum Values" registry.

   Property Name:  The name(s) of the property or properties where these
      values may be used.  This MUST be registered in the "JSContact
      Properties" registry.

   Context:  The list of allowed object types where the property or
      properties may appear, as registered in the "JSContact Properties"
      registry.  This disambiguates where there may be two distinct
      properties with the same name in different contexts.

   Since Version:  The JSContact version on which the enum value
      definition is based.  The version MUST be one of the allowed
      values of the version property in the "JSContact Version" registry
      (see Table 1).

   Until Version:  The JSContact version after which the enum value
      definition was obsoleted; therefore, the enum value definition
      MUST NOT be used in later versions.  The Until Version value
      either MUST NOT be set or MUST be one of the allowed values of the
      version property in the "JSContact Version" registry (see
      Table 1).

   Change Controller:  Person or entity responsible for requesting a
      change to the entry's definition ("IETF" for RFCs from the IETF
      stream).

   Reference or Description:  A brief description or RFC number and
      section reference for the semantics of the value.

   Note that the initial contents will be the initial list of defined
   values for the enum, using the template defined in Section 3.7.2.  A
   subregistry will be created with these values for this property name/
   context tuple.

3.7.2.  JSContact Enum Values Registry Value Template

   This template is for adding a new enum value to a subregistry in the
   "JSContact Enum Values" registry.

   Enum Value:  The verbatim value of the enum.

   Since Version:  The JSContact version on which the enum value
      definition is based.  The version MUST be one of the allowed
      values of the version property in the "JSContact Version" registry
      (see Table 1).

   Until Version:  The JSContact version after which the enum value was
      obsoleted; therefore, the enum value MUST NOT be used in later
      versions.  The Until Version value either MUST NOT be set or MUST
      be one of the allowed values of the version property in the
      "JSContact Version" registry (see Table 1).

   Change Controller:  Person or entity responsible for requesting a
      change to the entry's definition ("IETF" for RFCs from the IETF
      stream).

   Reference or Description:  A brief description or RFC number and
      section reference for the semantics of the value.

3.7.3.  Initial Contents of the JSContact Enum Values Registry

   For all entries in each subregistry created in this section, the
   Since Version is "1.0", the Until Version is not set, the Change
   Controller is "IETF", and RFC section references are for RFC 9553.

   Property Name:      contexts
   Context:            Address

   Initial Contents: 
                       +============+=======================+
                       | Enum Value | Reference/Description |
                       +============+=======================+
                       | billing    | Section 2.5.1.1       |
                       +------------+-----------------------+
                       | delivery   | Section 2.5.1.1       |
                       +------------+-----------------------+
                       | private    | Section 1.5.1         |
                       +------------+-----------------------+
                       | work       | Section 1.5.1         |
                       +------------+-----------------------+

                         Table 6: JSContact Enum Values for
                            contexts (Context: Address)

   Property Name:      contexts
   Context:            Calendar, CryptoKey, Directory, EmailAddress,
                       LanguagePref, Link, Media, Nickname,
                       OnlineService, Organization, Phone, Pronouns,
                       SchedulingAddress

   Initial Contents: 
                       +============+=======================+
                       | Enum Value | Reference/Description |
                       +============+=======================+
                       | private    | Section 1.5.1         |
                       +------------+-----------------------+
                       | work       | Section 1.5.1         |
                       +------------+-----------------------+

                         Table 7: JSContact Enum Values for
                            contexts (Context: Calendar,
                               CryptoKey, Directory,
                         EmailAddress, LanguagePref, Link,
                          Media, Nickname, OnlineService,
                           Organization, Phone, Pronouns,
                                 SchedulingAddress)

   Property Name:      features
   Context:            Phone

   Initial Contents: 
                       +=============+=======================+
                       | Enum Value  | Reference/Description |
                       +=============+=======================+
                       | fax         | Section 2.3.3         |
                       +-------------+-----------------------+
                       | main-number | Section 2.3.3         |
                       +-------------+-----------------------+
                       | mobile      | Section 2.3.3         |
                       +-------------+-----------------------+
                       | pager       | Section 2.3.3         |
                       +-------------+-----------------------+
                       | text        | Section 2.3.3         |
                       +-------------+-----------------------+
                       | textphone   | Section 2.3.3         |
                       +-------------+-----------------------+
                       | video       | Section 2.3.3         |
                       +-------------+-----------------------+
                       | voice       | Section 2.3.3         |
                       +-------------+-----------------------+

                          Table 8: JSContact Enum Values for
                              features (Context: Phone)

   Property Name:      grammaticalGender
   Context:            SpeakToAs

   Initial Contents: 
                       +============+=======================+
                       | Enum Value | Reference/Description |
                       +============+=======================+
                       | animate    | Section 2.2.4         |
                       +------------+-----------------------+
                       | common     | Section 2.2.4         |
                       +------------+-----------------------+
                       | feminine   | Section 2.2.4         |
                       +------------+-----------------------+
                       | inanimate  | Section 2.2.4         |
                       +------------+-----------------------+
                       | masculine  | Section 2.2.4         |
                       +------------+-----------------------+
                       | neuter     | Section 2.2.4         |
                       +------------+-----------------------+

                         Table 9: JSContact Enum Values for
                            grammaticalGender (Context:
                                     SpeakToAs)

   Property Name:      kind
   Context:            AddressComponent

   Initial Contents: 
                       +===============+=======================+
                       | Enum Value    | Reference/Description |
                       +===============+=======================+
                       | apartment     | Section 2.5.1.2       |
                       +---------------+-----------------------+
                       | block         | Section 2.5.1.2       |
                       +---------------+-----------------------+
                       | building      | Section 2.5.1.2       |
                       +---------------+-----------------------+
                       | country       | Section 2.5.1.2       |
                       +---------------+-----------------------+
                       | direction     | Section 2.5.1.2       |
                       +---------------+-----------------------+
                       | district      | Section 2.5.1.2       |
                       +---------------+-----------------------+
                       | floor         | Section 2.5.1.2       |
                       +---------------+-----------------------+
                       | landmark      | Section 2.5.1.2       |
                       +---------------+-----------------------+
                       | locality      | Section 2.5.1.2       |
                       +---------------+-----------------------+
                       | name          | Section 2.5.1.2       |
                       +---------------+-----------------------+
                       | number        | Section 2.5.1.2       |
                       +---------------+-----------------------+
                       | postcode      | Section 2.5.1.2       |
                       +---------------+-----------------------+
                       | postOfficeBox | Section 2.5.1.2       |
                       +---------------+-----------------------+
                       | region        | Section 2.5.1.2       |
                       +---------------+-----------------------+
                       | room          | Section 2.5.1.2       |
                       +---------------+-----------------------+
                       | separator     | Section 2.5.1.2       |
                       +---------------+-----------------------+
                       | subdistrict   | Section 2.5.1.2       |
                       +---------------+-----------------------+

                          Table 10: JSContact Enum Values for
                            kind (Context: AddressComponent)

   Property Name:      kind
   Context:            Anniversary

   Initial Contents: 
                       +============+=======================+
                       | Enum Value | Reference/Description |
                       +============+=======================+
                       | birth      | Section 2.8.1         |
                       +------------+-----------------------+
                       | death      | Section 2.8.1         |
                       +------------+-----------------------+
                       | wedding    | Section 2.8.1         |
                       +------------+-----------------------+

                          Table 11: JSContact Enum Values
                          for kind (Context: Anniversary)

   Property Name:      kind
   Context:            Calendar

   Initial Contents: 
                       +============+=======================+
                       | Enum Value | Reference/Description |
                       +============+=======================+
                       | calendar   | Section 2.4.1         |
                       +------------+-----------------------+
                       | freeBusy   | Section 2.4.1         |
                       +------------+-----------------------+

                          Table 12: JSContact Enum Values
                            for kind (Context: Calendar)

   Property Name:      kind
   Context:            Card

   Initial Contents: 
                       +=============+=======================+
                       | Enum Value  | Reference/Description |
                       +=============+=======================+
                       | application | Section 2.1.4         |
                       +-------------+-----------------------+
                       | device      | Section 2.1.4         |
                       +-------------+-----------------------+
                       | group       | Section 2.1.4         |
                       +-------------+-----------------------+
                       | individual  | Section 2.1.4         |
                       +-------------+-----------------------+
                       | location    | Section 2.1.4         |
                       +-------------+-----------------------+
                       | org         | Section 2.1.4         |
                       +-------------+-----------------------+

                         Table 13: JSContact Enum Values for
                                 kind (Context: Card)

   Property Name:      kind
   Context:            Directory

   Initial Contents: 
                       +============+=======================+
                       | Enum Value | Reference/Description |
                       +============+=======================+
                       | directory  | Section 2.6.2         |
                       +------------+-----------------------+
                       | entry      | Section 2.6.2         |
                       +------------+-----------------------+

                          Table 14: JSContact Enum Values
                           for kind (Context: Directory)

   Property Name:      kind
   Context:            Link

   Initial Contents: 
                       +============+=======================+
                       | Enum Value | Reference/Description |
                       +============+=======================+
                       | contact    | Section 2.6.3         |
                       +------------+-----------------------+

                          Table 15: JSContact Enum Values
                              for kind (Context: Link)

   Property Name:      kind
   Context:            Media

   Initial Contents: 
                       +============+=======================+
                       | Enum Value | Reference/Description |
                       +============+=======================+
                       | logo       | Section 2.6.4         |
                       +------------+-----------------------+
                       | photo      | Section 2.6.4         |
                       +------------+-----------------------+
                       | sound      | Section 2.6.4         |
                       +------------+-----------------------+

                          Table 16: JSContact Enum Values
                             for kind (Context: Media)

   Property Name:      kind
   Context:            NameComponent

   Initial Contents: 
                       +============+=======================+
                       | Enum Value | Reference/Description |
                       +============+=======================+
                       | credential | Section 2.2.1.2       |
                       +------------+-----------------------+
                       | generation | Section 2.2.1.2       |
                       +------------+-----------------------+
                       | given      | Section 2.2.1.2       |
                       +------------+-----------------------+
                       | given2     | Section 2.2.1.2       |
                       +------------+-----------------------+
                       | separator  | Section 2.2.1.2       |
                       +------------+-----------------------+
                       | surname    | Section 2.2.1.2       |
                       +------------+-----------------------+
                       | surname2   | Section 2.2.1.2       |
                       +------------+-----------------------+
                       | title      | Section 2.2.1.2       |
                       +------------+-----------------------+

                          Table 17: JSContact Enum Values
                         for kind (Context: NameComponent)

   Property Name:      kind
   Context:            PersonalInfo

   Initial Contents: 
                       +============+=======================+
                       | Enum Value | Reference/Description |
                       +============+=======================+
                       | expertise  | Section 2.8.4         |
                       +------------+-----------------------+
                       | hobby      | Section 2.8.4         |
                       +------------+-----------------------+
                       | interest   | Section 2.8.4         |
                       +------------+-----------------------+

                          Table 18: JSContact Enum Values
                          for kind (Context: PersonalInfo)

   Property Name:      kind
   Context:            Title

   Initial Contents: 
                       +============+=======================+
                       | Enum Value | Reference/Description |
                       +============+=======================+
                       | role       | Section 2.2.5         |
                       +------------+-----------------------+
                       | title      | Section 2.2.5         |
                       +------------+-----------------------+

                          Table 19: JSContact Enum Values
                             for kind (Context: Title)

   Property Name:      level
   Context:            PersonalInfo

   Initial Contents: 
                       +============+=======================+
                       | Enum Value | Reference/Description |
                       +============+=======================+
                       | high       | Section 2.8.4         |
                       +------------+-----------------------+
                       | low        | Section 2.8.4         |
                       +------------+-----------------------+
                       | medium     | Section 2.8.4         |
                       +------------+-----------------------+

                          Table 20: JSContact Enum Values
                         for level (Context: PersonalInfo)

   Property Name:      phoneticSystem
   Context:            Address, Name

   Initial Contents: 
                       +============+=======================+
                       | Enum Value | Reference/Description |
                       +============+=======================+
                       | ipa        | Section 1.5.4         |
                       +------------+-----------------------+
                       | jyut       | Section 1.5.4         |
                       +------------+-----------------------+
                       | piny       | Section 1.5.4         |
                       +------------+-----------------------+

                          Table 21: JSContact Enum Values
                            for phoneticSystem (Context:
                                   Address, Name)

   Property Name:      relation
   Context:            Relation

   Initial Contents: 
                       +==============+=======================+
                       | Enum Value   | Reference/Description |
                       +==============+=======================+
                       | acquaintance | Section 2.1.8         |
                       +--------------+-----------------------+
                       | agent        | Section 2.1.8         |
                       +--------------+-----------------------+
                       | child        | Section 2.1.8         |
                       +--------------+-----------------------+
                       | colleague    | Section 2.1.8         |
                       +--------------+-----------------------+
                       | contact      | Section 2.1.8         |
                       +--------------+-----------------------+
                       | co-resident  | Section 2.1.8         |
                       +--------------+-----------------------+
                       | co-worker    | Section 2.1.8         |
                       +--------------+-----------------------+
                       | crush        | Section 2.1.8         |
                       +--------------+-----------------------+
                       | date         | Section 2.1.8         |
                       +--------------+-----------------------+
                       | emergency    | Section 2.1.8         |
                       +--------------+-----------------------+
                       | friend       | Section 2.1.8         |
                       +--------------+-----------------------+
                       | kin          | Section 2.1.8         |
                       +--------------+-----------------------+
                       | me           | Section 2.1.8         |
                       +--------------+-----------------------+
                       | met          | Section 2.1.8         |
                       +--------------+-----------------------+
                       | muse         | Section 2.1.8         |
                       +--------------+-----------------------+
                       | neighbor     | Section 2.1.8         |
                       +--------------+-----------------------+
                       | parent       | Section 2.1.8         |
                       +--------------+-----------------------+
                       | sibling      | Section 2.1.8         |
                       +--------------+-----------------------+
                       | spouse       | Section 2.1.8         |
                       +--------------+-----------------------+
                       | sweetheart   | Section 2.1.8         |
                       +--------------+-----------------------+

                         Table 22: JSContact Enum Values for
                             relation (Context: Relation)

4.  Security Considerations

   Contact information is very privacy sensitive.  It can reveal the
   identity, location, credentials information, employment status,
   interests and hobbies, and social network of a user.  Its
   transmission and storage must be done carefully to protect it from
   possible threats such as eavesdropping, replay, message insertion,
   deletion, modification, and on-path attacks.

   The data being stored and transmitted may be used in systems with
   real-world consequences.  For example, a malicious actor might
   provide JSContact data that uses the name of another person but
   insert their contact details to impersonate the unknown victim.  Such
   systems must be careful to authenticate all data they receive to
   prevent them from being subverted and ensure the change comes from an
   authorized entity.

   This document only defines the data format; such considerations are
   primarily the concern of the API or method of storage and
   transmission of such files.

4.1.  JSON Parsing

   The security considerations of [RFC8259] apply to the use of JSON as
   the data interchange format.

   As for any serialization format, parsers need to thoroughly check the
   syntax of the supplied data.  JSON uses opening and closing brackets
   for several types and structures, and it is possible that the end of
   the supplied data will be reached when scanning for a matching
   closing bracket; this is an error condition, and implementations need
   to stop scanning at the end of the supplied data.

   JSON also uses a string encoding with some escape sequences to encode
   special characters within a string.  Care is needed when processing
   these escape sequences to ensure that they are fully formed before
   the special processing is triggered, with special care taken when the
   escape sequences appear adjacent to other (non-escaped) special
   characters or adjacent to the end of data (as in the previous
   paragraph).

   If parsing JSON into a non-textual structured data format,
   implementations may need to allocate storage to hold JSON string
   elements.  Since JSON does not use explicit string lengths, the risk
   of denial of service due to resource exhaustion is small, but
   implementations may still wish to place limits on the size of
   allocations they are willing to make in any given context, to avoid
   untrusted data causing excessive memory allocation.

4.2.  URI Values

   Several JSContact properties contain URIs as values, and processing
   these properties requires extra care.  Section 7 of [RFC3986]
   discusses security risks related to URIs.

   Fetching remote resources carries inherent risks.  Connections must
   only be allowed on well-known ports, using allowed protocols
   (generally, just HTTP/HTTPS on their default ports).  The URL must be
   resolved externally and not allowed to access internal resources.
   Connecting to an external source reveals IP (and therefore often
   location) information.

   A maliciously constructed JSContact object may contain a very large
   number of URIs.  In the case of published address books with a large
   number of subscribers, such objects could be widely distributed.
   Implementations should be careful to limit the automatic fetching of
   linked resources to reduce the risk of this being an amplification
   vector for a denial-of-service attack.

5.  References

5.1.  Normative References

   [IANA-TZ]  IANA, "Time Zone Database",
              <https://www.iana.org/time-zones>.

   [IANA-vCard]
              IANA, "vCard Elements",
              <https://www.iana.org/assignments/vcard-elements>.

   [ISO.3166-1]
              International Organization for Standardization, "Codes for
              the representation of names of countries and their
              subdivisions -- Part 1: Country codes", ISO 3166-1:2020,
              August 2020.

   [RFC1034]  Mockapetris, P., "Domain names - concepts and facilities",
              STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,
              <https://www.rfc-editor.org/info/rfc1034>.

   [RFC1035]  Mockapetris, P., "Domain names - implementation and
              specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
              November 1987, <https://www.rfc-editor.org/info/rfc1035>.

   [RFC2046]  Freed, N. and N. Borenstein, "Multipurpose Internet Mail
              Extensions (MIME) Part Two: Media Types", RFC 2046,
              DOI 10.17487/RFC2046, November 1996,
              <https://www.rfc-editor.org/info/rfc2046>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC2426]  Dawson, F. and T. Howes, "vCard MIME Directory Profile",
              RFC 2426, DOI 10.17487/RFC2426, September 1998,
              <https://www.rfc-editor.org/info/rfc2426>.

   [RFC3339]  Klyne, G. and C. Newman, "Date and Time on the Internet:
              Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
              <https://www.rfc-editor.org/info/rfc3339>.

   [RFC4648]  Josefsson, S., "The Base16, Base32, and Base64 Data
              Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006,
              <https://www.rfc-editor.org/info/rfc4648>.

   [RFC5234]  Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", STD 68, RFC 5234,
              DOI 10.17487/RFC5234, January 2008,
              <https://www.rfc-editor.org/info/rfc5234>.

   [RFC5322]  Resnick, P., Ed., "Internet Message Format", RFC 5322,
              DOI 10.17487/RFC5322, October 2008,
              <https://www.rfc-editor.org/info/rfc5322>.

   [RFC5646]  Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying
              Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646,
              September 2009, <https://www.rfc-editor.org/info/rfc5646>.

   [RFC5870]  Mayrhofer, A. and C. Spanring, "A Uniform Resource
              Identifier for Geographic Locations ('geo' URI)",
              RFC 5870, DOI 10.17487/RFC5870, June 2010,
              <https://www.rfc-editor.org/info/rfc5870>.

   [RFC6350]  Perreault, S., "vCard Format Specification", RFC 6350,
              DOI 10.17487/RFC6350, August 2011,
              <https://www.rfc-editor.org/info/rfc6350>.

   [RFC6901]  Bryan, P., Ed., Zyp, K., and M. Nottingham, Ed.,
              "JavaScript Object Notation (JSON) Pointer", RFC 6901,
              DOI 10.17487/RFC6901, April 2013,
              <https://www.rfc-editor.org/info/rfc6901>.

   [RFC7493]  Bray, T., Ed., "The I-JSON Message Format", RFC 7493,
              DOI 10.17487/RFC7493, March 2015,
              <https://www.rfc-editor.org/info/rfc7493>.

   [RFC7529]  Daboo, C. and G. Yakushev, "Non-Gregorian Recurrence Rules
              in the Internet Calendaring and Scheduling Core Object
              Specification (iCalendar)", RFC 7529,
              DOI 10.17487/RFC7529, May 2015,
              <https://www.rfc-editor.org/info/rfc7529>.

   [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
              Writing an IANA Considerations Section in RFCs", BCP 26,
              RFC 8126, DOI 10.17487/RFC8126, June 2017,
              <https://www.rfc-editor.org/info/rfc8126>.

   [RFC8141]  Saint-Andre, P. and J. Klensin, "Uniform Resource Names
              (URNs)", RFC 8141, DOI 10.17487/RFC8141, April 2017,
              <https://www.rfc-editor.org/info/rfc8141>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8259]  Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
              Interchange Format", STD 90, RFC 8259,
              DOI 10.17487/RFC8259, December 2017,
              <https://www.rfc-editor.org/info/rfc8259>.

5.2.  Informative References

   [IPA]      IPA, "International Phonetic Alphabet",
              <https://www.internationalphoneticalphabet.org/>.

   [RFC3261]  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
              A., Peterson, J., Sparks, R., Handley, M., and E.
              Schooler, "SIP: Session Initiation Protocol", RFC 3261,
              DOI 10.17487/RFC3261, June 2002,
              <https://www.rfc-editor.org/info/rfc3261>.

   [RFC3966]  Schulzrinne, H., "The tel URI for Telephone Numbers",
              RFC 3966, DOI 10.17487/RFC3966, December 2004,
              <https://www.rfc-editor.org/info/rfc3966>.

   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66,
              RFC 3986, DOI 10.17487/RFC3986, January 2005,
              <https://www.rfc-editor.org/info/rfc3986>.

   [RFC3987]  Duerst, M. and M. Suignard, "Internationalized Resource
              Identifiers (IRIs)", RFC 3987, DOI 10.17487/RFC3987,
              January 2005, <https://www.rfc-editor.org/info/rfc3987>.

   [RFC6351]  Perreault, S., "xCard: vCard XML Representation",
              RFC 6351, DOI 10.17487/RFC6351, August 2011,
              <https://www.rfc-editor.org/info/rfc6351>.

   [RFC6473]  Saint-Andre, P., "vCard KIND:application", RFC 6473,
              DOI 10.17487/RFC6473, December 2011,
              <https://www.rfc-editor.org/info/rfc6473>.

   [RFC6474]  Li, K. and B. Leiba, "vCard Format Extensions: Place of
              Birth, Place and Date of Death", RFC 6474,
              DOI 10.17487/RFC6474, December 2011,
              <https://www.rfc-editor.org/info/rfc6474>.

   [RFC6715]  Cauchie, D., Leiba, B., and K. Li, "vCard Format
              Extensions: Representing vCard Extensions Defined by the
              Open Mobile Alliance (OMA) Converged Address Book (CAB)
              Group", RFC 6715, DOI 10.17487/RFC6715, August 2012,
              <https://www.rfc-editor.org/info/rfc6715>.

   [RFC6869]  Salgueiro, G., Clarke, J., and P. Saint-Andre, "vCard
              KIND:device", RFC 6869, DOI 10.17487/RFC6869, February
              2013, <https://www.rfc-editor.org/info/rfc6869>.

   [RFC7095]  Kewisch, P., "jCard: The JSON Format for vCard", RFC 7095,
              DOI 10.17487/RFC7095, January 2014,
              <https://www.rfc-editor.org/info/rfc7095>.

   [RFC8605]  Hollenbeck, S. and R. Carney, "vCard Format Extensions:
              ICANN Extensions for the Registration Data Access Protocol
              (RDAP)", RFC 8605, DOI 10.17487/RFC8605, May 2019,
              <https://www.rfc-editor.org/info/rfc8605>.

   [RFC9499]  Hoffman, P. and K. Fujiwara, "DNS Terminology", BCP 219,
              RFC 9499, DOI 10.17487/RFC9499, March 2024,
              <https://www.rfc-editor.org/info/rfc9499>.

   [RFC9554]  Stepanek, R. and M. Loffredo, "vCard Format Extensions for
              JSContact", RFC 9554, DOI 10.17487/RFC9554, May 2024,
              <https://www.rfc-editor.org/info/rfc9554>.

   [RFC9555]  Stepanek, R. and M. Loffredo, "JSContact: Converting from
              and to vCard", RFC 9555, DOI 10.17487/RFC9555, May 2024,
              <https://www.rfc-editor.org/info/rfc9555>.

   [RFC9562]  Davis, K., Peabody, B., and P. Leach, "Universally Unique
              IDentifiers (UUIDs)", RFC 9562, DOI 10.17487/RFC9562, May
              2024, <https://www.rfc-editor.org/info/rfc9562>.

   [UBiDi]    The Unicode Consortium, "Unicode Standard Annex #9:
              Unicode Bidirectional Algorithm", Revision 48,
              Unicode 15.1.0, August 2023,
              <https://www.unicode.org/reports/tr9/>.

   [WHATWG-URL]
              WHATWG, "URL Living Standard", January 2024,
              <https://url.spec.whatwg.org>.

Authors' Addresses

   Robert Stepanek
   Fastmail
   PO Box 234
   Collins St. West
   Melbourne VIC 8007
   Australia
   Email: rsto@fastmailteam.com


   Mario Loffredo
   IIT-CNR
   Via Moruzzi, 1
   56124 Pisa
   Italy
   Email: mario.loffredo@iit.cnr.it