"Heading is descriptive" (b49b2e): replace "section of content"

[Jym77]

Change the expectation to remove "section of content" and replace it with "the next palpable content" (according to https://www.w3.org/2020/07/23-act-r-minutes.html#item01).

Doing minimal changes to get the fix working. Notably not splitting the rule for visible/accessible headings (it feels much needed now), and not cleaning up the rest of the rule (will be done once we want to submit it to TF review).

Closes issue(s):

• closes "Heading is descriptive" (b49b2e) What do heading need to describe? #1361
• closes Metadata in glossary #1085 (comment)

Need for Final Call:
This will require a 1 week Final Call (changing expectation)

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[Jym77]

This strongly suggest that this rule should be split in two, one for each case…

[EmmaJP]

Not if those 'and' conditional are intentional. I read this as:

If the target is visible and included in the accessibility tree, then it should describe the first palpable content that is visible and included in the accessibility tree that comes after the target in the flat tree.

However, what about non-visible headings describing visible content, where both are included in the accessibility tree? This is not an unusual use case, eg. a news front page with a hidden heading 'Top headlines'. The heading isn't needed visually as that is usually apparent from other cues.

That also makes me question the phrasing of the applicability. Should it not be ' visible and/or included in the accessibility tree'?

[Jym77]

If it is both visible and included in the accessibility tree, then it is "visible or included in the accessibility tree" (the or is inclusive by default). And then it matches both the expectations and need to describe both visible and accessible content (which may be the same or different palpable content).

[kasperisager]

I like it! 👏

Rest of the changes done

[kasperisager]

Isn't the rule essentially assuming conformance to 1.3.2 (https://www.w3.org/TR/WCAG/#meaningful-sequence)? In that case, it seems like an even more reasonable assumption to make.

[Jym77]

Not really, because the programmatically determined order could be different from the DOM order (and match the visual order). For example by tweaking the accessibility tree with aria-owns.

[kasperisager]

Makes sense 👍 I also just looked into CSS Grid and, interestingly enough, grid layouts that re-arrange the logical order of content are non-conforming: https://drafts.csswg.org/css-grid/#order-accessibility

[EmmaJP]

Not to mention the fun that can ensue when flexbox gets involved!

[EmmaJP]

I think some fine tuning is still needed with the phrasing of the applicability and expectation sections. Other than that, I think this is really starting to shape up well.

Split expectation in two

[Jym77]

Final Call ends on September 23rd.

[Jym77]

Final Call has ended. Merging.