Explanation

The unknown value indicates that a publisher has not yet checked their publication for hazards or is unsure whether some content might present a hazard.

This value should typically only be used as a temporary placeholder if a publication must be released before an accessibility review can be completed.

The unknown value should not be used with any other hazard value. It is the equivalent of setting unknownFlashingHazard, unknownMotionSimulationHazard, and unknownSoundHazard.

Examples

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

ONIX Mapping

The unknown value does not have a single value equivalent in ONIX. It is the same as setting list 143 codes 24, 25, and 26.

Related Links