Update accessibility.md (#3985)

* Update accessibility.md

Adding an update for manifests and limitations of our survey.

* Put in aside

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Co-authored-by: Barry Pollard <barrypollard@google.com>

Author: mgifford

src/content/en/2024/accessibility.md

@@ -562,6 +562,8 @@ The `<track>` element is used to provide timed text for `<audio>` and `<video>`
 
 For `<video>` elements, the figure is slightly higher at 0.5% for both desktops and 0.65% for mobile sites. These statistics do not cover audio or video embedded via `<iframe>`, where third-party services are less likely to offer text alternatives. Our industry can do a lot better.
 
+<aside class="note">The methodology to collect the data for this report did not include modern HLS (HTTP Live Streaming) which would would include a manifest file to include subtitles for the deaf and hard-of-hearing (SDH). In the future, scanning for this would allow better understanding of what languages are supported with closed captions and also collect information about the use of audio description.</aside>
+
 ## Assistive technology with ARIA
 
 <a hreflang="en" href="https://www.w3.org/TR/using-aria/">Accessible Rich Internet Applications (ARIA)</a> provides a set of attributes for HTML5 elements designed to enhance web accessibility for individuals with disabilities. However, excessive use of ARIA attributes can sometimes create more problems than it solves. ARIA should be employed only when native HTML5 elements are inadequate for ensuring a fully accessible experience and should not replace or be used beyond what is necessary.