Note: This is kind of old document, not updated since 2018 and still mostly in a draft state, but I think it may be useful for someone.
Adds mechanisms to the Atom Syndication Format that publishers of Atom Feed and Entry documents can use to explicitly identify Atom entries that have been removed.
Uses prefix at: to indicate namespace http://purl.org/atompub/tombstones/1.0.
| Extension | Type | Description |
|---|---|---|
at:deleted-entry |
element | Represents an Atom Entry that has been removed. |
at:by |
element | Identifies the entity that removed the entry. |
at:comment |
element | Provides additional, language-sensitive information about the deletion operation. |
Defines an extension to the Atom Syndication Format for describing licenses associated with Atom feeds and entries.
| Extension | Type | Description |
|---|---|---|
license |
link relation | Associates licenses with a feed or entry. |
The Atom Publishing Protocol (AtomPub) is an application-level protocol for publishing and editing Web resources.
Uses prefix app: to indicate namespace http://www.w3.org/2007/app.
| Extension | Type | Description |
|---|---|---|
app:control |
element | |
app:draft |
element | Represents a request by the client to control the visibility of a Member Resource. |
app:edited |
element | Indicates the last time an Entry was edited.. |
edit |
link relation | Refers to a resource that can be used to edit the |
edit-media |
link relation | Refers to a resource that can be used to edit media associated with the link’s context. |
Presents a mechanism that allows feeds publishers to express threaded discussions within the Atom Syndication Format.
Uses prefix thr: to indicate namespace http://purl.org/syndication/thread/1.0.
| Extension | Type | Description |
|---|---|---|
thr:count |
attribute | (for atom:link[@rel='replies']) Provides a hint to clients as to the total number of replies contained by the linked resource. |
thr:in-reply-to |
element | Indicates that an entry is a response to another resource. |
thr:total |
element | Indicates the total number of unique responses to an entry known to the publisher. |
thr:updated |
attribute | (for atom:link[@rel='replies']) Provides a hint to clients as to the date and time of the most recently updated reply contained by the linked resource. |
replies |
link relation | References a resource where responses to an entry may be found. |
Defines three types of syndicated Web feeds that enable publication of entries across one or more feed documents.
Uses prefix fh: to indicate namespace http://purl.org/syndication/history/1.0.
| Extension | Type | Description |
|---|---|---|
fh:archive |
element | Indicates that the feed document it occurs in is an archived feed. |
fh:complete |
element | Indicates that the feed document it occurs in is a complete representation of the logical feed’s entries. |
current |
link relation | Refers to the feed document containing the most recent entries in the feed. |
first |
link relation | Refers to the furthest preceding document in a series of documents. |
last |
link relation | Refers to the furthest following document in a series of documents. |
next |
link relation | Refers to the immediately following document in a series of documents. |
next-archive |
link relation | Refers to the immediately following archive document. |
previous |
link relation | Refers to the immediately preceding document in a series of documents. |
prev-archive |
link relation | Refers to the immediately preceding archive document. |
Defines a resource-oriented approach for security automation information publication, discovery, and sharing.
Uses prefix rolie: to indicate namespace urn:ietf:params:xml:ns:rolie-1.0.
| Extension | Type | Description |
|---|---|---|
rolie:format |
element | Describes the data model used to express the information referenced in the atom:content element. |
rolie:property |
element | Provides a way to associate a name/value pair of categorical information. |
Disclaimer:
It is inappropriate to use Internet-Drafts as reference material or to cite them other than as “work in progress.”
Defines elements identifying an intended redistribution target for the entry.
| Extension | Type |
|---|---|
atom:to |
element |
atom:cc |
element |
atom:bcc |
element |
Adds a new attribute to the Atom Syndication Format used to indicate the base directionality of directionally-neutral characters.
| Extension | Type | Description |
|---|---|---|
atom:dir |
attribute (common) | Specifies the base direction of directionally-neutral text. |
In order to increase content visibility, many publishers are now duplicating their content or a summary thereof on other sites. The document describes an extension to the Atom syndication format for declaring such duplicates such that feed consumers which see both may detect this usage.
Uses prefix crosspost: to indicate namespace http://purl.org/syndication/cross-posting.
| Extension | Type | Description |
|---|---|---|
crosspost:source |
element | Indicates that the corresponding entry is a secondary duplicate and that the entry described by its attributes is the corresponding primary version. |
crosspost:target |
element | Indicates that the corresponding entry is a primary version and that the entry described by its attributes is a secondary duplicate. |
Adds additional attributes to the Atom Syndication Format link and content elements that may be used to express additional metadata about linked resources.
| Extension | Type | Description |
|---|---|---|
atom:accessed |
attribute | (for atom:content | atom:link) Specifies the most recent date and time when the resource was accessed by the producer of the Atom document. |
atom:etag |
attribute | (for atom:content | atom:link) Specifies an Entity Tag for the resource. |
atom:hash |
attribute | (for atom:content | atom:link) Specifies a whitespace-delimited list of hash digest values calculated over the resource. |
atom:modified |
attribute | (for atom:content | atom:link) Specifies the date and time when the resource was last modified. |
Presents a mechanism that allows feed publishers to express preferences over how a consumer processes Atom links and Content-By-Reference.
Uses prefix x: to indicate namespace http://purl.org/atompub/nofollow/1.0.
| Extension | Type | Description |
|---|---|---|
x:archive |
attribute | (for atom:content[@src] | atom:link) Indicates whether applications should archive the targets of links and content references. |
x:follow |
attribute | (for atom:content[@src] | atom:link) Indicates whether applications should automatically attempt to follow links and referenced content. |
x:index |
attribute | (for atom:content[@src] | atom:link) Indicates whether applications should index links and referenced content. |
Defines a link relation that enables an Atom document to point to a venue for multi-party discussion of the document or its primary topic.
| Extension | Type | Description |
|---|---|---|
discuss |
link relation | References an Internet resource where multi-party discussion of the feed, entry, or source can occur. |
Presents a mechanism that allows feed publishers to express maximum age and expiration properties for information content within an Atom entry.
Uses prefix age: to indicate namespace http://purl.org/atompub/age/1.0.
| Extension | Type | Description |
|---|---|---|
age:expires |
element | Indicates a precise moment in time after which the information content of the containing element MUST be considered to have “expired”. |
age:max-age |
element | Indicates a maximum age of the information content after which the information content MUST be considered to have “expired”. |
Introduces weblog specific publishing control extensions for use with the Atom Publishing Protocol pub:control mechanism.
Uses prefix blog: to indicate namespace http://purl.org/atompub/blogcontrols/1.0.
| Extension | Type | Description |
|---|---|---|
blog:comments |
element | Specifies whether to enable comments for the entry. |
blog:comments-notify |
element | Specifies whether or not notifications should be sent when new comments are posted. |
blog:enable |
element | Specifies whether specific features should be enabled for the entry. |
blog:notify |
element | Specifies a collection of endpoints that should be notified upon the creation or update of the entry. |
blog:pingbacks |
element | Specifies whether to enable pingbacks for the entry. |
blog:pingbacks-notify |
element | Specifies whether or not notifications should be sent when new pingbacks are posted. |
blog:plugin |
element | Specifies an IRI identifying a plugin to enable for the post. |
blog:private |
element | Indicates that a weblog entry should only be made available to a limited audience. |
blog:scheduled |
element | Specifies a date and time that indicates when the posted entry should be published. |
blog:text-encoding |
element | Specifies an IRI identifying a text-encoding scheme to apply to the post. |
blog:trackbacks |
element | Specifies whether to enable trackbacks for the entry. |
blog:trackbacks-notify |
element | Specifies whether or not notifications should be sent when new trackbacks are posted. |
Defines an Atom Syndication Format extension for numerically ranking entries within a syndication feed.
Uses prefix re: to indicate namespace http://purl.org/atompub/rank/1.0.
| Extension | Type | Description |
|---|---|---|
re:rank |
element | Conveys a numeric rank associated with an entry. |
Defines extensions to the Atom Syndication Format Person Construct.
Uses prefix pe: to indicate namespace http://purl.org/atompub/person-extensions/1.0.
| Extension | Type | Description |
|---|---|---|
pe:identity |
element | Associates an identity token with an author or contributor. |
pe:profile |
element | Rich metadata descriptions about an individual author or contributor. |
pe:role |
element | Associates a specific contribution role with an author or contributor. |
Defines metadata extensions for use with the Atom Syndication Format to track revisions of entries.
Uses prefix ar: to indicate namespace http://purl.org/atompub/revision/1.0.
| Extension | Type | Description |
|---|---|---|
ar:by |
element | Identifies the person or entity that removed the entry from the feed. |
ar:comment |
element | Provides the equivalent to editorial notes. |
ar:deleted-entry |
element | Represents an Atom Entry that has been removed from the feed. |
ar:host |
element | Either the IP Address or Domain host name from which the person created or modified the entry. |
ar:revision |
element | Identifies a “revision number” for an entry. |
ar:when |
element | Specifies the instant the entry was deleted. |
current-revision |
link relation | Specifies the URI of an Atom Entry Document representing the current version of the entry. |
diff |
link relation | Identifies a resource describing the deltas between this revision of the entry and the previous revision. |
history |
link relation | Identifies a resource describing the revision history of the entry. |
initial-revision |
link relation | Specifies the URI of an Atom Entry Document representing the initial version of the entry. |
next-revision |
link relation | Specifies the URI of an Atom Entry Document representing the subsequent version of the entry. |
prior-revision |
link relation | Specifies the URI of an Atom Entry Document representing the previous version of the entry. |
this-revision |
link relation | Specifies the URI of an Atom Entry Document representing this version of the entry. |
Describes AtomTriples, a set of Atom extension elements for embedding RDF statements in Atom documents (both element and feed), and declaring how they can be derived from existing content.
Uses prefix at: to indicate namespace http://purl.org/syndication/atomtriples/1.
| Extension | Type | Description |
|---|---|---|
at:entrymap |
element | Indicates mappings for entry-level element contents to statements. |
at:feedmap |
element | Indicates mappings for feed-level element contents to statements. |
at:map |
element | Indicates how an element in a given context maps to RDF statementsentry. |
at:md |
element | Contains any number of RDF statements serialised as RDF/XML. |
The Feed Item Query Language is a simple but flexible, URI-friendly syntax for expressing filters across the entries in a Web feed.
Uses prefix fq: to indicate namespace http://purl.org/syndication/query.
| Extension | Type | Description |
|---|---|---|
fq:index |
element | Indicates a selector that is available for use in queries. |
fq:interface |
element | Describes an interface that processes queries for the feed it occurs in. |
Defines link relations for hierarchical navigation among Atom feeds and entries.
| Extension | Type | Description |
|---|---|---|
down |
link relation | References a resource where child entries of an entry may be found. |
up |
link relation | References a resource where parent entries of an entry or a feed may be found. |
Defines “cache channels” to propagate out-of-band events from HTTP origin servers (or their delegates) to subscribing caches.
Uses prefix cc: to indicate namespace http://purl.org/syndication/cache-channel.
| Extension | Type | Description |
|---|---|---|
cc:lifetime |
element | Indicates an Atom cache channel’s lifetime. |
cc:precision |
element | Indicates an Atom cache channel’s precision. |
Defines mechanisms for in-lining representations of linked Atom resources.
Uses prefix ae: to indicate namespace http://purl.org/atom/ext/.
| Extension | Type | Description |
|---|---|---|
ae:inline |
element | Contains an approximate representation of the linked resource. |
Introduces an attribute for representing Japanese phonetics within feeds of the Atom Syndication Format.
Uses prefix jepa: to indicate namespace http://www.jepa.or.jp/xmlns/atomPhonetics/1.0.
| Extension | Type | Description |
|---|---|---|
jepa:phonetics |
attribute | (for atom:name | atom:subtitle | atom:title) Represents the phonetics for a Japanese author name or article title. |
The OpenSearch response elements can be used by search engines to augment existing XML formats with search-related metadata.
Uses prefix opensearch: to indicate namespace http://a9.com/-/spec/opensearch/1.1/.
<opensearch:totalResults> element containing the number of search results available for the current search.<opensearch:startIndex> element containing the index of the first search result in the current set of search results.<opensearch:itemsPerPage> element containing the number of search results returned per page.<opensearch:Query> element defining a search query that can be performed by search clients.The OpenSearch Advertisement Extension allows search engines to include advertisements with search results.
Uses prefix ad: to indicate namespace http://a9.com/-/opensearch/extensions/advertisement/1.0/.
<ad:advertisement> element specifying an advertisement related to the search results.<ad:callOut> element specifying a textual marker that identifies this content as an advertisement.<ad:title> element specifying the title of the advertisement.<ad:subTitle> element specifying the subtitle text of the advertisement.<ad:displayUrl> element specifying the advertisement domain name or URL.<ad:image> element specifying an image displayed in the advertisement.The OpenSearch Commerce Extension allows search engines to include information about previewing and purchasing digital commerce items in search results.
Uses prefix com: to indicate namespace http://a9.com/-/opensearch/extensions/commerce/1.0/.
<com:adultContent> element specifying whether the item contains age-restricted content.<com:attribution> element specifying a contractually-obligated attribution to be displayed with the digital commerce item.<com:label> element specifying the label to display alongsite the digital commerce item.<com:partnerId> element specifying a unique identifier of a browsable or consumable digital commerce item in a partner content catalog.<com:price> element specifying the purchase terms, price and currency for a consumable digital commerce item.<com:rating> element specifying a numeric rating for a content item.The purpose of the OpenSearch Mobile extensions is to provide a standard mechanism for querying mobile-centric and PC-centric data providers and displaying results relevant for mobile subscribers and devices.
Uses prefix m: to indicate namespace http://a9.com/-/opensearch/extensions/mobile/1.0/.
<m:device> element describing the mobile device targeted by the search results.<m:subscriber> element identifying the mobile subscriber targeted by the search results.next-page, page-#, section, detail and spelling link relations.The OpenSearch Relevance Extension allows search engines indicate a relative score in a particular domain for an individual search result.
Uses prefix relevance: to indicate namespace http://a9.com/-/opensearch/extensions/relevance/1.0/.
<relevance:score> element containing a string indicating a relative assessment of relevance for a particular search result with respect to the search query.The OpenSearch Spelling Extension allows search engines to include information about a spelling suggestion in the search results.
Uses prefix spell: to indicate namespace http://a9.com/-/opensearch/extensions/spelling/1.0/.
<spell:spelling> element suggesting a spelling correction for the query.<spell:suggestion> element specifying the suggested spelling correction for the query.<spell:prompt> element specifying the prompt text displayed near the spelling suggestion.<spell:related> element suggesting search terms that are related to the current query but are not spelling corrections.An XML format that allows activities on social objects to be expressed within the Atom Syndication Format.
Uses prefix activity: to indicate namespace http://activitystrea.ms/spec/1.0/.
| Extension | Type | Description |
|---|---|---|
activity:object |
element | Identifies the primary object of the activity. |
activity:object-type |
element | Identifies the type of object. |
activity:target |
element | Identifies the object to which the activity was performed. |
activity:verb |
element | Identifies the action of the activity. |
Specifies Extension elements and link relations for the Atom Syndication Format useful for description of metadata specific to the wiki engines.
Uses prefix wiki: to indicate namespace https://wandystan.eu/ns/AtomWiki/0.3/.
Link relations must be preceded with https://wandystan.eu/ns/AtomWiki/0.3/.
| Extension | Type | Description |
|---|---|---|
wiki:host |
element | The host associated with the person that edited the wiki page. |
wiki:revision |
element | Indicates that the entry it occurs in represents a revision of a wiki page. |
diff |
link relation | Refers to the resource describing the difference between a previous and the current revision of the page. |
first-revision |
link relation | Refers to the earliest revision of the page. |
history |
link relation | Refers to the resource describing the revision history of the page. |
last-revision |
link relation | Refers to the latest revision of the page. |
next-revision |
link relation | Refers to the next revision of the page. |
prev-revision |
link relation | Refers to the previous revision of the page. |
revision-of |
link relation | Refers to the page that the entry is a revision of. |
GeoRSS was designed as a lightweight, community driven way to extend existing feeds with geographic information.
GeoRSS can be used both in Atom and RSS 2.0 feeds, and also as an RDF ontology.
Uses prefix georss: to indicate namespace http://www.georss.org/georss.
| Extension | Type | Description |
|---|---|---|
georss:box |
element | A bounding box is a rectangular region, often used to define the extents of a map or a rough area of interest. |
georss:elev |
element | Contains common GPS elevation readings, i.e. height in meters from the WGS84 ellipsoid. |
georss:featurename |
element | Feature Name. |
georss:featuretypetag |
element | Feature Type. |
georss:floor |
element | Contains the floor number of a building. |
georss:line |
element | A line. |
georss:point |
element | A point. |
georss:polygon |
element | A polygon. |
georss:radius |
element | Indicates the size in meters of a radius or buffer around the geometry object. |
georss:relationshiptag |
element | Relationship tag. |
georss:where |
element | Signals geographic content – either in GeoRSS Simple or GML. |
The Google Data Protocol provides a secure means for external developers to write new applications that let end users access and update the data stored by many Google products.
Uses prefix gd: to indicate namespace http://schemas.google.com/g/2005.
| Extension | Type | Description |
|---|---|---|
gd:additionalName |
element | Specifies additional (eg. middle) name of the person. |
gd:comments |
element | Contains a comments feed for the enclosing entry. |
gd:deleted |
element | A marker element that, when present, indicates the containing entry is deleted. |
gd:country |
element | Country name along with optional country code. |
gd:email |
element | An email address associated with the containing entity. |
gd:etag |
attribute | Identifier that specifies a particular version of a particular entry. |
gd:entryLink |
element | Represents a logically nested entry. |
gd:extendedProperty |
element | Allows you to store a limited amount of custom data as an auxiliary property of the enclosing entity. |
gd:familyName |
element | Specifies family name of the person. |
gd:feedLink |
element | Represents a logically nested feed. |
gd:fields |
attribute | Response filter. |
gd:geoPt |
element | (deprecated) A geographical location (latitude, longitude, elevation). |
gd:im |
element | An instant messaging address associated with the containing entity. |
gd:image |
element | (undocumented, found in Blogspot feeds) |
gd:givenName |
element | Specifies given name of the person. |
gd:money |
element | Specifies an amount of money in a particular currency. |
gd:name |
element | Allows storing person’s name in a structured way. |
gd:organization |
element | An organization, typically associated with a contact. |
gd:orgDepartment |
element | Describes a department within an organization. |
gd:orgJobDescription |
element | Describes a job within an organization. |
gd:orgName |
element | The name of the organization. |
gd:orgSymbol |
element | Provides a symbol of an organization. |
gd:orgTitle |
element | The title of a person within an organization. |
gd:originalEvent |
element | Equivalent to the Recurrence ID property specified in section 4.8.4.4 of RFC 2445. |
gd:phoneNumber |
element | A phone number associated with the containing entity. |
gd:postalAddress |
element | A postal address. |
gd:rating |
element | Represents a numeric rating of the enclosing entity, such as a comment. |
gd:recurrence |
element | Represents the dates and times when a recurring event takes place. |
gd:recurrenceException |
element | Represents an event that’s an exception to a recurring event. |
gd:reminder |
element | A time interval. |
gd:resourceId |
element | An opaque resource identifier, distinct from atom:id as it need not be a valid URI |
gd:structuredPostalAddress |
element | Postal address split into components. |
gd:when |
element | Represents a period of time or an instant. |
gd:where |
element | A place (such as an event location) associated with the containing entity. |
gd:who |
element | A person associated with the containing entity. |
Uses prefix mastodon: to indicate namespace http://mastodon.social/schema/1.0.
| Extension | Type | Description |
|---|---|---|
mastodon:scope |
element | Specifies Mastodon account or status scope. |
The Open Data Protocol (OData) for representing and interacting with structured content is comprised of a set of specifications. The core specification for the protocol is in OData Version 4.0 Part 1: Protocol. This document extends the core specification by defining representations for OData requests and responses using an Atom format.
TODO: Add summary of extensions defined by the specification.
The Open Publication Distribution System (OPDS) Catalog format is a syndication format for electronic publications based on Atom and HTTP. OPDS Catalogs enable the aggregation, distribution, discovery, and acquisition of electronic publications.
Uses prefix odps: to indicate namespace http://opds-spec.org/2010/catalog.
Link relations must be preceded with http://opds-spec.org/.
| Extension | Type | Description |
|---|---|---|
opds:activeFacet |
attribute | (for atom:link[@rel='http://opds-spec.org/facet']) Indicates that a Facet is active. |
opds:facetGroup |
attribute | (for atom:link[@rel='http://opds-spec.org/facet']) Groups Facets together. |
opds:price |
element | Represents the acquisition price in a particular currency of an individual Publication in a particular format from a particular provider. |
opds:indirectAcquisition |
element | Represents these secondary media types that the client can expect to acquire if they follow the Acquisition Link. |
acquisition |
link relation | A generic relation that indicates that the complete representation of the content Resource may be retrieved. |
acquisition/open-access |
link relation | Indicates that the complete representation of the Resource can be retrieved without any requirement, which includes payment and registration. |
acquisition/borrow |
link relation | Indicates that the complete representation of the content Resource may be retrieved as part of a lending transaction. |
acquisition/buy |
link relation | Indicates that the complete representation of the content Resource may be retrieved as part of a purchase. |
acquisition/sample |
link relation | Indicates that a subset of the content Resource may be retrieved. |
acquisition/subscribe |
link relation | Indicates that the complete representation of the content Resource may be retrieved as part of a subscription. |
crawlable |
link relation | An optimized Acquisition Feed. |
facet |
link relation | An Acquisition Feed with a subset or an alternate order of the Publications listed. |
featured |
link relation | An Acquisition Feed with featured OPDS Catalog Entries. |
image |
link relation | A graphical Resource associated to the OPDS Catalog Entry. |
image/thumbnail |
link relation | A reduced-size version of a graphical Resource associated to the OPS Catalog Entry. |
recommended |
link relation | An Acquisition Feed with recommended OPDS Catalog Entries. |
shelf |
link relation | A Resource that includes a user’s existing set of Acquired Content, which MAY be represented as an OPDS Catalog. |
sort/new |
link relation | An Acquisition Feed with newly released OPDS Catalog Entries. |
sort/popular |
link relation | An Acquisition Feed with popular OPDS Catalog Entries. |
subscriptions |
link relation | A Resource that includes a user’s set of subscriptions, which MAY be represented as an OPDS Catalog. |
Details an OAI-ORE Resource Map serialization based on the Atom syndication format, in which each Resource Map is expressed as an Atom entry.
Uses prefix oreatom: to indicate namespace http://www.openarchives.org/ore/atom/.
| Extension | Type | Description |
|---|---|---|
oreatom:triples |
element | Allows to embed RDF statements. |
OStatus is a minimal specification for distributed status updates or microblogging.
Uses prefix ostatus: to indicate namespace http://ostatus.org/schema/1.0/.
| Extension | Type | Description |
|---|---|---|
ostatus:attention |
link relation | When an update is directed to the attention of someone, or mentions someone, this link stores that user’s URI. |
ostatus:conversation |
link relation | When an update is part of a distributed conversation, this is the URI of that conversation. |
ostatus:conversation |
element | (undocumented, found in Mastodon and GNU Social feeds) |
ostatus:object-type |
attribute | (undocumented, found in Mastodon and GNU Social feeds) |
Use prefix feedburner: to indicate namespace http://rssnamespace.org/feedburner/ext/1.0.
<feedburner:info> and <feedburner:origLink> elements.| Extension | Type |
|---|---|
feedburner:info |
element |
feedburner:origLink |
element |
Found in Feedburner feeds.
Use prefix statusnet: to indicate namespace http://status.net/schema/api/1/.
| Extension | Type |
|---|---|
statusnet:notice_info |
element |
statusnet:profile_info |
element |
followers |
element |
status_net |
element |
Found in GNU Social feeds.
Use prefix media: to indicate namespace http://purl.org/syndication/atommedia.
| Extension | Type |
|---|---|
media:height |
attribute for atom:link |
media:width |
attribute for atom:link |
Found in:
Use prefix yt: to indicate namespace http://www.youtube.com/xml/schemas/2015.
| Extension | Type |
|---|---|
yt:channelId |
element |
yt:videoId |
element |
Found in YouTube channel feeds.
An RSS module that supplements the <enclosure> element capabilities of RSS 2.0 to allow for more robust media syndication.
Uses prefix media: to indicate namespace http://search.yahoo.com/mrss/.
<media:group> element allowing grouping of content elements.<media:content> element embedding media objects.<media:category>, <media:comments>, <media:community>, <media:copyright>, <media:credit>, <media:description>, <media:hash>, <media:keywords>, <media:license>, <media:price>, <media:rating>, <media:responses>, <media:restriction>, <media:rights>, <media:status>, <media:subTitle> and <media:title> metadata elements.<media:backLinks>, <media:embed>, <media:param>, <media:peerLink>, <media:player> and <media:thumbnail> elements pointing to additional resources.<media:scenes>, <media:scene>, <sceneTitle>, <sceneDescription>, <sceneStartTime> and <sceneEndTime> elements specifying various scenes within a media object.<media:text> element allowing the inclusion of a text transcript, closed captioning, or lyrics of the media content.Found in YouTube channel feeds.
The Portable Contacts specification is designed to make it easier for developers to give their users a secure way to access the address books and friends lists they have built up all over the web.
Feeds use prefix poco: to indicate namespace http://portablecontacts.net/spec/1.0.
<poco:preferredUsername>, <poco:displayName>, <poco:note>, <poco:address>, <poco:formatted>, <poco:urls>, <poco:type>, <poco:value>, <poco:primary> and other (not found in any feed) elements.Found in: