Definition

Indicates that the author has not yet checked if the resource contains accessibility features.

Examples

Example 1 — EPUB 3
<meta property="schema:accessibilityFeature">
   unknown
</meta>
Example 2 — EPUB 2
<meta name="schema:accessibilityFeature"
      content="unknown"/>
Example 3 — Audiobooks
"accessibilityFeature": ["unknown"]

Explanation

The unknown value indicates the accessibility features of a publication are not known. Only use this value when a publication has not been evaluated for accessibility as it is not useful for readers.

Do not use the unknown value with any other accessibility feature values.

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