Clarification of description of aria-details for ARIA action 2107.

aria/aria.html

@@ -8903,8 +8903,9 @@ <h2>Definitions of States and Properties (all aria-* attributes)</h2>
 			<pdef>aria-details</pdef>
 			<div class="property-description">
 				<p>[ARIA 1.1] Identifies the <a>element</a> that provides a detailed, extended description for the <a>object</a>. See related <pref>aria-describedby</pref>.</p>
-				<p>The <code>aria-details</code> attribute references a single element that provides more detailed information than would normally be provided by <pref>aria-describedby</pref>. Unlike <code>aria-describedby</code>, authors SHOULD ensure the content is not hidden and is included in a container that exposes the content to the user as it is expected that the assistive technology user navigate to the content to access it. This is often because converting the contents to a string results in either a loss of information or a decreased understanding of the object being described. Consequently, <code>aria-details</code> does not participate in either the Accessible <a href="https://www.w3.org/TR/accname-aam-1.1/#mapping_additional_nd_name">Name Computation</a> or the Accessible <a href="https://www.w3.org/TR/accname-aam-1.1/#mapping_additional_nd_description">Description Computation</a> as defined in the Accessible Name and Description specification [[ACCNAME-AAM]].</p>
-				<p>When both <pref>aria-describedby</pref> and <code>aria-details</code> are provided on an element <code>aria-details</code> takes precedence.</p>
+				<p>The <code>aria-details</code> attribute references a single element that provides more detailed information than would normally be provided by <pref>aria-describedby</pref>. It enables <a>assistive technologies</a> to make users aware of the availability of an extended description as well as navigate to it. Authors SHOULD ensure the element referenced by <code>aria-details</code> is visible to all users.</p>
+				<p>Unlike elements referenced by <code>aria-describedby</code>, the element referenced by <code>aria-details</code> is not used in either the Accessible <a href="https://www.w3.org/TR/accname-aam-1.1/#mapping_additional_nd_name">Name Computation</a> or the Accessible <a href="https://www.w3.org/TR/accname-aam-1.1/#mapping_additional_nd_description">Description Computation</a> as defined in the Accessible Name and Description specification [[ACCNAME-AAM]]. Thus, the content of an element referenced by <code>aria-details</code> is not flattened to a string when presented to assistive technology users. This makes <code>aria-details</code> particularly useful when converting the information to a string would cause a loss of information or make the extended description more difficult to understand.</p>
+				<p>In some user agents, multiple reference relationships for descriptive information are not supported by the accessibility API. In such cases, if both <pref>aria-describedby</pref> and <code>aria-details</code> are provided on an element, <code>aria-details</code> takes precedence.</p>
 				<p>A common use for <code>aria-details</code> is in digital publishing where an extended description needs to be conveyed in a book that requires structural markup or the embedding of other technology to provide illustrative content. The following example demonstrates this scenario.</p>
 				<pre class="example highlight">
                                 &lt;!-- Provision of an extended description --&gt;