Copyright © 2023 the Contributors to the Schema.org Accessibility Properties for Discoverability Vocabulary Specification, published by the Accessibility Discoverability Vocabulary for Schema.org Community Group under the W3C Community Final Specification Agreement (FSA). A human-readable summary is available.
This document defines the recommended vocabularies for use with the Schema.org accessibility properties for discoverability of creative works.
This specification was published by the Accessibility Discoverability Vocabulary for Schema.org Community Group. It is not a W3C Standard nor is it on the W3C Standards Track. Please note that under the W3C Community Final Specification Agreement (FSA) other conditions apply. Learn more about W3C Community and Business Groups.
GitHub Issues are preferred for discussion of this specification.
The CreativeWork type [schema-org]
includes the following accessibility properties for discoverability:
accessibilityAPIaccessibilityControlaccessibilityFeatureaccessibilityHazardaccessibilitySummaryaccessModeaccessModeSufficientAlthough schema.org contains many other properties that describe the accessibility of objects in its taxonomy, these specific properties were developed together as part of a project to improve the discoverability of accessible resources headed by Benetech and IMS Global. Many of these properties were derived directly from the IMS Global AccessForAll (AfA) Information Model Data Element Specification.
Part of this work included defining vocabularies of recommended values for use with these properties to ensure predictability for machine processing. This document represents those vocabularies.
By defining these vocabularies, not only is it simpler for authors to understand and apply the properties, but it ensures that search tools, user agents and other machine intelligence can easily parse and inform users of the information.
The vocabulary defined in this document is a continuation of the work that was informally hosted on the WebSchemas wiki (sometimes referred to as the "version 2.0 accessibility properties"). The project was moved to a W3C Community Group to better formalize the document and increase the transparency of its update process.
For more information about the original project, refer to the Accessibility Metadata Project's web site.
For more information on how to use schema.org accessibility properties not covered by this vocabulary, please refer to their relevant definitions in schema.org.
The values defined in this vocabulary follow a camel casing convention: single words are lowercase, while compound words are concatenated into a single value with a capital letter indicating the start of each connected word (e.g., "alternativeText"). This convention is not applied to acronyms, accessibility APIs, and other values that already have recognized naming conventions (e.g., "MathML" and "iOSAccessibility").
To ensure maximum interoperability with user agents that process these properties, use the values exactly as they are defined in this vocabulary. Alternative case spellings may not be recognized (e.g., "mathml" or "aria").
User agent developers should be aware that these values may not be strictly validated depending on the context in which they are created and used. Two values that differ only in case should be treated as identical.
To extend terms with more information, this vocabulary used to recommend the old slash extension syntax employed by Schema.org until 2015. In this model, extensions of a term are made by adding a slash followed by a refinement term.
Authors are no longer recommended to use this extension mechanism, although the use of slashes is not formally deprecated for backwards compatibility with existing content. The slash syntax was poorly defined, especially when multiple refinements could be specified, making it difficult for machines to process.
When a user may require more information about the characteristics of a resource (e.g., the specifics of what type of braille it contains), it is better to explain these in human-readable terms in an accessibility summary.
If a term in this vocabulary is not be expressive enough, it is now recommended to open an issue in the tracker to consider how to improve the existing term (e.g., by renaming terms or defining more specialized cases).
Indicates that the resource is compatible with the referenced accessibility API.
Compatibility with an accessibility API indicates that assistive technologies on the platform should be able to access the resource.
The property is not applicable to resources that are not tightly integrated with their user interface. It can describe whether a word processing document that only opens in a specific application will work on a given platform, for example, but is not a useful indicator of whether an HTML document will, as there are numerous user agents a user could use to render it.
Setting the property means that the resource is compatible with the given API(s). It does not necessarily mean that the content will be fully accessible to any given user group.
The expected value of the accessibilityAPI property is a list of the compatible APIs.
For metadata formats incapable of expressing lists, the property should be repeated for each
API.
Indicates the resource is compatible with the Android Access API.
Indicates the resource uses ARIA [WCAG21] markup to improve interoperability with platform APIs.
The use of the ARIA value is now deprecated as ARIA is not an accessibility API. The
accessibilityFeature property value "ARIA" is now recommended
to use to indicate that a resource makes use of ARIA to improve structural navigation.
Indicates the resource is compatible with the Accessibility Toolkit (ATK) API [ATK] for GNOME.
Indicates the resource is compatible with the Assistive Technology Service Provider Interface (AT-SPI) API [AT-SPI] for GNOME.
Indicates the resource is compatible with the BlackBerry Accessibility API.
This value is now obsolete as BlackBerry devices phones and operating systems are no longer developed, sold, or maintained.
After 2016, the BlackBerry name was licensed for phones released using the Android platform.
Compatibility with these devices must be indicated using the AndroidAccessibility value.
Indicates the resource is compatible with the Fuchsia Accessibility Framework.
Indicates the resource is compatible with the iAccessible2 API [IAccessible2] for Windows.
Authors should use the NSAccessibility value instead.
Indicates the resource is compatible with the Java Accessibility API [JAPI].
Authors should use the UIAccessibility value instead.
Indicates the resource is compatible with the Microsoft Active Accessibility (MSAA) API [MSAA] for Windows.
Indicates the resource is compatible with the NSAccessibility API for Apple iOS and tvOS applications built on UIKit.
Indicates the resource is compatible with the UIAccessibility API for macOS applications built on AppKit.
Indicates the resource is compatible with the User Interface Automation API for Windows.
Identifies one or more input methods that allow access to all of the application functionality.
The accessibilityControl property is used to describe the ability of users to interact
with the user interface controls that applications provide.
The property is not applicable to resources that are not tightly integrated with their user interface. It can describe whether users can control a word processing document that only opens in a specific application, for example, but is not a useful indicator of whether users can control an HTML document, as there are numerous user agent and assistive technology pairings a user could use to access it.
Setting the property means that the specified control method(s) are compatible with the resource.
The expected value of the accessibilityControl property is a list of the applicable
control methods. For metadata formats incapable of expressing lists, the property should be repeated
for each control method.
Users can fully control the resource through keyboard input.
Users can fully control the resource through mouse input.
Users can fully control the resource through switch input.
Users can fully control the resource through touch input.
Users can fully control the resource through video input.
Users can fully control the resource through voice input.
Content features of the resource, such as accessible media, alternatives and supported enhancements for accessibility.
The accessibilityFeature property provides a list of all the applicable accessibility
characteristics of the content. It allows a user agent to discover these characteristics without
having to parse or interpret the structure of the content.
For ease of reading, this section splits the vocabulary into the following distinct groups:
alt attribute is one of the most commonly identifiable augmentation
features.The vocabulary also includes the term "none" that authors
can set to indicate that the resource does not contain special enhancements. Similarly, the term
"unknown" exists as a placeholder for marking content that authors need to
review.
The expected value of the accessibilityFeature property is a list of the applicable
features. For metadata formats incapable of expressing lists, the property should be repeated for
each feature.
The adaptation terms identify provisions in the content that enable reading in alternative access modes.
Alternative text is provided for visual content (e.g., via the [HTML] alt attribute).
Audio descriptions are available (e.g., via an [HTML] track element with its kind attribute set to
"descriptions").
Indicates that synchronized captions are available for audio and video content.
The use of the captions value is now deprecated. Authors should use the more
specific closedCaptions or openCaptions values, as appropriate.
Indicates that synchronized closed captions are available for audio and video content.
Closed captions are defined separately from the video, allowing users to control whether they are rendered or not, unlike open captions.
Textual descriptions of math equations are included, whether in the alt attribute for
image-based equations, using the alttext attribute for [MathML] equations, or by other means.
Descriptions are provided for image-based visual content and/or complex structures such as tables, mathematics, diagrams, and charts.
Authors may set this property independent of the method they use to provide the extended
descriptions (i.e., it is not required to use the obsolete [HTML] longdesc attribute).
Indicates that synchronized open captions are available for audio and video content.
Open captions are part of the video stream and cannot be turned off by the user, unlike closed captions.
Sign language interpretation is available for audio and video content.
Information about the sign language code used should be provided in the accessibility summary.
Indicates that a transcript of the audio content is available.
The rendering control values identify that access to a resource and rendering and playback of its content can be controlled for easier reading.
Display properties are controllable by the user. This property can be set, for example, if custom CSS style sheets can be applied to the content to control the appearance. It can also be used to indicate that styling in document formats like Word and PDF can be modified.
Describes a resource that offers both audio and text, with information that allows them to be rendered simultaneously. The granularity of the synchronization is not specified. This term is not recommended when the only material that is synchronized is the document headings.
For content with timed interaction, this value indicates that the user can control the timing to meet their needs (e.g., pause and reset)
No digital rights management or other content restriction protocols have been applied to the resource.
The specialized markup terms identify content available in specialized markup grammars. These grammars typically provide users with enhanced structure and navigation capabilities.
Identifies that chemical information is encoded using the ChemML markup language.
Identifies that mathematical equations and formulas are encoded in the LaTeX typesetting system.
Identifies that mathematical equations and formulas are encoded in [MathML].
One or more of [SSML], [Pronunciation-Lexicon], and [CSS3-Speech] properties has been used to enhance text-to-speech playback quality.
The clarity terms identify ways that the content has been enhanced for improved auditory or visual clarity.
Audio content with speech in the foreground meets the contrast thresholds set out in WCAG Success Criteria 1.4.7.
Information about the how the audio meets the requirement should be provided in the accessibility summary (i.e., there is no background noise, at least 20db difference between foreground speech and background noise, or the background noise can be turned off.)
Content meets the visual contrast threshold set out in WCAG Success Criteria 1.4.6.
The content has been formatted to meet large print guidelines.
The property is not set if the font size can be increased. See displayTransformability.
Information about the type of large print (e.g., the font size) should be provided in the accessibility summary.
The tactile terms identify content that is available in tactile form.
The content is in braille format, or alternatives are available in braille.
Information about the type of braille (e.g., ASCII, unicode, nemeth), whether the braille is contracted or not, and what code the braille conforms to should be provided in the accessibility summary.
When used with creative works such as books, indicates that the resource includes tactile graphics.
When used to describe an image resource or physical object, indicates that the resource is a tactile graphic.
Refer to the BANA Guidelines and Standards for Tactile Graphics for more information about tactile graphic formats and formatting.
When used with creative works such as books, indicates that the resource includes models to generate tactile 3D objects.
When used to describe a physical object, indicates that the resource is a tactile 3D object.
The internationalization terms identify those accessibility characteristics of the content which are required for internationalization.
Indicates that ruby annotations [JLreq] are attached to every CJK ideographic character in the content. Ruby annotations are used as pronunciation guides for the logographic characters for languages like Chinese or Japanese. They make difficult CJK ideographic characters more accessible.
If some but not all CJK ideographic characters have ruby annotations, use the rubyAnnotations value.
Indicates that the content can be laid out horizontally (e.g, using the
horizontal-tb writing mode of [css-writing-modes-3]). This value should
only be set when the language of the content allows both horizontal and vertical directions.
Notable examples of such languages are Chinese, Japanese, and Korean.
Some dyslexic Japanese can read horizontal writing but cannot read vertical writing.
Indicates that ruby annotations are attached to some but not all CJK ideographic characters in the content.
If all CJK ideographic characters have ruby annotations, use the fullRubyAnnotations value.
Indicates that the content can be laid out vertically (e.g, using the
vertical-rl of [css-writing-modes-3]). This value should only be set when
the language of the content allows both horizontal and vertical directions.
Indicates that the content can be rendered with additional word segmentation.
Although the space character is not typically used for word segmentation in languages such as Chinese, Japanese, Thai and Lao, it may be used for accessibility reasons.
Indicates that the content can be rendered without additional word segmentation.
Indicates that the resource does not contain any accessibility features.
The none value must not be set with any other feature value.
Indicates that the author has not yet checked if the resource contains accessibility features. This value is only intended as a placeholder until an accessibility review can be completed.
The unknown value must not be set with any other feature value.
A characteristic of the described resource that is physiologically dangerous to some users. Related to WCAG 2.0 guideline 2.3.
Identifying potential hazards that a resource poses allows users to determine if a resource poses a risk to them and to potentially filter out content that could be harmful.
The expected value of the accessibilityHazard property is a list of the applicable
hazards. For metadata formats incapable of expressing lists, the property should be repeated for
each hazard.
The accessibilityHazard property currently allows three types of hazards to be
identified: flashing, motion simulation, and sound. These correspond to the values
flashing, motionSimulation, and sound.
It also allows authors to indicate that each of the hazards is not present. In this case, the values
follow the pattern "no…Hazard", using the hazard names in place of the ellipsis
(e.g., noFlashingHazard).
If the author is sure there are no hazards, they are recommended to use the value "none"
in place of specifying that each individual hazard is not present. When setting this value, no other
hazard statuses are allowed.
Authors can additionally indicate that they are unable to determine if a hazard is present. In this
case, the values follow the pattern "unknown…Hazard", using the hazard names in
place of the ellipsis (e.g., unknownSoundHazard).
Authors can set the value unknown if they are unsure whether any hazards are present
(e.g., because they do not know how, or are unable, to assess them). When setting this value, no
other hazard statuses are allowed.
Indicates that the resource presents a flashing hazard for photosensitive persons.
This value should be set when the content meets the hazard thresholds described in Success Criterion 2.3.1 Three Flashes or Below Threshold [WCAG2].
The flashing value must not be set when any of the noFlashingHazard, unknownFlashingHazard, none, or unknown values is
set.
Indicates that the resource contains instances of motion simulation that may affect some individuals.
Some examples of motion simulation include video games with a first-person perspective and CSS-controlled backgrounds that move when a user scrolls a page.
The motionSimulation value must not be set when any of the noMotionSimulationHazard, unknownMotionSimulationHazard, none, or unknown values is set.
Indicates that the resource contains auditory sounds that may affect some individuals.
The application of this value is currently under discussion as its application is underspecified.
The sound value must not be set when any of the noSoundHazard, unknownSoundHazard, none,
or unknown values are set.
Indicates that the resource does not contain any hazards.
It is recommended to use the none value when there are no hazards instead of
individual statements for noSoundHazard, noMotionSimulationHazard, and noFlashingHazard.
The none value must not be set when specifying either a known hazard or the unknown value. It should not be set when
negative hazard claims are made.
Indicates that the resource does not present a flashing hazard.
The noFlashingHazard value must not be set when any of the flashing, unknownFlashing, or unknown values is set.
It should not be set when the none value is set.
Indicates that the resource does not contain instances of motion simulation.
The noMotionSimulation value must not be set when any of the motionSimulation, unknownMotionSimulationHazard, or
unknown values is set.
It should not be set when the none value is set.
Indicates that the resource does not contain auditory hazards.
The application of this value is currently under discussion as its application is underspecified.
The noSoundHazard value must not be set when either of the sound, unknownSoundHazard, or unknown values is set.
It should not be set when the none value is set.
Indicates that the author is not able to determine if the resource presents any hazards.
It is recommended to use the unknown value when all hazards are unknown instead
of individual statements for unknownSoundHazard, unknownMotionSimulationHazard, and unknownFlashingHazard.
The unknown value must not be set when specifying either a known hazard or the
none value. It should not be set with the
individual unknown hazard value.
Indicates that the author cannot determine if a flashing hazard exists.
The unknownFlashingHazard value must not be set when any of the flashing, noFlashingHazard, none
values is set.
It should not be set when the unknown value is
set.
Indicates that it is unknown if a motion simulation hazard exists within the content.
The unknownMotionSimulation value must not be set when any of the motionSimulation, noMotionSimulationHazard or none values is set.
It should not be set when the unknown value is
set.
Indicates that it is unknown if an auditory hazard exists within the content.
The unknownSoundHazard value must not be set when either of the sound, unknownSoundHazard, or unknown values is set.
It should not be set when the none value is set.
A human-readable summary of specific accessibility features or deficiencies, consistent with the other accessibility metadata but expressing subtleties such as "short descriptions are present but long descriptions will be needed for non-visual users" or "short descriptions are present and no long descriptions are needed."
The accessibilitySummary property is a free-form field that allows authors to describe the
accessible properties of the resource. As a result, it does not have an associated vocabulary.
The human sensory perceptual system or cognitive faculty through which a person may process or perceive information.
The accessMode property describes the ways information is encoded in the resource, where
information is defined as any content that contributes to the understanding of the resource.
The expected value of the accessMode property is a list of the applicable access modes.
For metadata formats incapable of expressing lists, the property should be repeated for each access
mode.
The access modes do not tell users if all the specified modes are necessary to consume the information or if only individual modes or combinations are necessary (e.g., in a book with audio content, the ability to read textual content may be sufficient if transcripts are provided).
The accessModeSufficient property is designed to
fill this gap of understanding the combinations of modes necessary to fully consume the
information.
Indicates that the resource contains information encoded in auditory form.
This value is not set when the auditory content conveys no information. For example, an instructional video might include background music while all the necessary information to complete the task is conveyed visually and/or through text captions.
Indicates that the resource contains charts encoded in visual form.
Indicates that the resource contains chemical equations encoded in visual form.
Indicates that the resource contains information encoded such that color perception is necessary.
Indicates that the resource contains diagrams encoded in visual form.
Indicates that the resource contains mathematical notations encoded in visual form.
Indicates that the resource contains musical notation encoded in visual form.
Indicates that the resource contains information encoded in tactile form.
Note that although an indication of a tactile mode often indicates the content is encoded using a braille system, this is not always the case. Tactile perception may also indicate, for example, the use of tactile graphics to convey information.
Indicates that the resource contains text encoded in visual form.
Indicates that the resource contains information encoded in textual form.
This value is not set if the only textual content is for navigational purposes. For example, an audiobook might include a table of contents, but it is not necessary to read the table of contents to read the work. Likewise, books with synchronized text-audio playback may only include headings to allow structured navigation.
Indicates that the resource contains information encoded in visual form.
This value is not set if the only visual imagery is presentational or not directly relevant to understanding the content. Examples of this type of imagery include cover images for publications, corporate logos, and purely decorative images.
A list of single or combined accessModes that are sufficient to understand all the intellectual content of a resource.
Although the access modes indicate how the information is encoded in its default form, knowing the encoding only describes one possible perceptual pathway through the content. For example, a book with textual and visual content will, at the most basic level, require an individual who can read text and view images.
The author of the content may, however, provide alternatives to a specific access mode that allow the content to be wholly consumed in another manner. The use of alternative text and extended descriptions, for example, can allow a user who cannot perceive visual content to read all the information in textual form (e.g., through text-to-speech playback).
In such a case, a resource with textual and visual access modes could have both a textual and visual sufficient access mode and a purely textual access mode — because there are text equivalents for the visual content. Specifying there is an additional textual-only pathway through the content allows users of screen readers, for example, to recognize that the content will be readable by them.
It is for this reason that content that has multiple access modes may have one or more sets of sufficient access modes: each listing of sufficient access modes provides users with one possible combination of reading modes that allow the content to be read in full.
Although listing the combinations of access modes that allow a user to read all the content is helpful, the most important sufficient access modes to list are the single-value ones. Users looking for an alternative to the default encoding of the content typically are looking for a single presentation mode (e.g., a fully textual pathway to use with a text-to-speech renderer or a fully auditory pathway to listen to).
The expected value of the accessModeSufficient property is an ItemList. Each entry in the ItemList must be a list of
one or more access modes representing one pathway.
For formats incapable of expressing lists, the property should be repeated for each set of sufficient access modes. In these cases, it is recommended to use a comma-separated list of values.
Indicates that auditory perception is necessary to consume the information.
Indicates that tactile perception is necessary to consume the information.
Indicates that the ability to read textual content is necessary to consume the information.
Note that reading textual content does not require visual perception, as textual content can be rendered as audio using a text-to-speech capable device or assistive technology.
Indicates that visual perception is necessary to consume the information.
The following example shows how accessibility metadata could be used to enhance a library record available on the Web.
<div itemscope="" itemtype="http://schema.org/Book">
<meta itemprop="bookFormat" content="EBook/DAISY3" />
<meta itemprop="accessibilityFeature" content="ARIA" />
<meta itemprop="accessibilityFeature" content="largePrint" />
<meta itemprop="accessibilityFeature" content="highContrastDisplay" />
<meta itemprop="accessibilityFeature" content="displayTransformability" />
<meta itemprop="accessibilityFeature" content="longDescription" />
<meta itemprop="accessibilityFeature" content="alternativeText" />
<meta itemprop="accessibilityFeature" content="readingOrder" />
<meta itemprop="accessibilityFeature" content="structuralNavigation" />
<meta itemprop="accessibilityFeature" content="tableOfContents" />
<meta itemprop="accessibilityControl" content="fullKeyboardControl" />
<meta itemprop="accessibilityControl" content="fullMouseControl" />
<meta itemprop="accessibilityHazard" content="none" />
<dl>
<dt>Name:</dt>
<dd itemprop="name">Holt Physical Science</dd>
<dt>Brief Synopsis:</dt>
<dd itemprop="description">NIMAC-sourced textbook</dd>
<dt>Long Synopsis:</dt>
<dd>N/A</dd>
<dt>Book Quality:</dt>
<dd>Publisher Quality</dd>
<dt>Book Size:</dt>
<dd itemprop="numberOfPages">598 Pages</dd>
<dt>ISBN-13:</dt>
<dd itemprop="isbn">9780030426599</dd>
<dt>Publisher:</dt>
<dd itemprop="publisher" itemtype="http://schema.org/Organization" itemscope="">Holt, Rinehart
and Winston</dd>
<dt>Date of Addition:</dt>
<dd>06/08/10</dd>
<dt>Copyright Date:</dt>
<dd itemprop="copyrightYear">2007</dd>
<dt>Copyrighted By:</dt>
<dd itemprop="copyrightHolder" itemtype="http://schema.org/Organization" itemscope="">Holt,
Rinehart and Winston</dd>
<dt>Adult content:</dt>
<dd><meta itemprop="isFamilyFriendly" content="true" />No</dd>
<dt>Language:</dt>
<dd><meta itemprop="inLanguage" content="en-US" />English US</dd>
<dt>Essential Images:</dt>
<dd>861</dd>
<dt>Described Images:</dt>
<dd>910</dd>
<dt>Categories:</dt>
<dd><span itemprop="genre">Educational Materials</span></dd>
<dt>Grade Levels:</dt>
<dd>Sixth grade, Seventh grade, Eighth grade</dd>
<dt>NIMAC:</dt>
<dd>This book is currently only available to public K-12 schools and organizations in the United
States for use with students with an IEP, because it was created from files supplied by the
NIMAC under these restrictions. Learn more in the NIMAC Support Center.</dd>
</dl>
<div class="bookReviews" itemprop="aggregateRating" itemscope=""
itemtype="http://schema.org/AggregateRating">
<h2>Reviews of Holt Physical Science (<span itemprop="reviewCount">0</span> reviews)</h2>
<div class="bookReviewScore">
<span><span itemprop="ratingValue">0</span> - No Rating Yet</span>
</div>
</div>
</div>This example shows how the accessibility metadata could be used to augment a record for a video.
<dl itemtype="http://schema.org/VideoObject" itemscope="">
<dt>Title:</dt>
<dd itemprop="name">Arctic Climate Perspectives</dd>
<dt>Description:</dt>
<dd itemprop="description">This video, adapted from material provided by the ECHO
partners, describes how global climate change is affecting Barrow, Alaska.</dd>
<dt>Adaptation Type:</dt>
<dd><span itemprop="accessibilityFeature">captions</span></dd>
<dt>Access Mode:</dt>
<dd>auditory, visual</dd>
<dt>URL:</dt>
<dd><a itemprop="url" href="http://www.example.org/asset/echo07_vid_climate"
>http://www.example.org/asset/echo07_vid_climate</a>/</dd>
<dt>Has Adaptation:</dt>
<dd>http://www.example.org/asset/echo07_vid_climate_dvs/</dd>
<dt>Subjects:</dt>
<dd><span itemprop="about">National K-12 Subject::Science::Earth and Space
Science::Water Cycle, Weather, and Climate::Structure and Composition of the
Atmosphere, National K-12 Subject::Science::Earth and Space Science::Water Cycle,
Weather, and Climate::Climate</span></dd>
<dt>Education Level:</dt>
<dd>Grade 6, Grade 7, Grade 8, Grade 9</dd>
<dt>Audience:</dt>
<dd><span itemprop="intendedEndUserRole">Learner</span></dd>
<dt>Resource Type:</dt>
<dd><span itemprop="genre">Audio/Visual</span>,
<span itemprop="genre">Movie/Animation</span></dd>
<dt>Language:</dt>
<dd><span itemprop="inLanguage">en-US</span></dd>
<dt>Publication Date:</dt>
<dd itemprop="datePublished">2007-02-12</dd>
<dt>Rights:</dt>
<dd>Download and Share, <a itemprop="useRightsUrl"
href="http://www.example.org/oerlicense/2/"
>http://www.example.org/oerlicense/2/</a></dd>
</dl>Note that this change log only identifies substantive changes to the vocabulary — those that add or deprecate terms, or are similarly noteworthy.
For a list of all issues addressed (typos, minor definition modifications, etc.), refer to the Community Group's issue tracker.
FuchsiaAccessibility to the accessibilityAPI
values. See issue 24.closedCaptions and openCaptions to replace the more
generic captions value. See issue 26.unknown feature for placeholder use. See issue 17.pageNavigation feature for indicating that a resource has a page
list. See issue 6.pageBreakMarkers feature for indicating that a resource includes
static page break markers. printPageNumbers is retained as a synonym but no longer
recommended for use. See issue
6.bookmarks feature due to its ambiguous definition. The
tableOfContents and annotations values are recommended in its
place. See issue 5.accessibilityFeature. See pull request 39.accessibilityAPI value "ARIA" is deprecated. It is replaced by a
new "ARIA" value for accessibilityFeature for indicating the use of roles of
enhanced structural and landmark navigation. See issue 4.The editors would like to thank the Accessibility Discoverability Vocabulary for Schema.org Community Group participants for their ongoing input and suggestions to improve this vocabulary.
Additional thanks go to the original participants of the Accessibility Metadata Project for their work bringing the properties and vocabularies to reality.