Thanks for the context! I'll readily admit that I'm no expert on the outline algorithm, but I will say that the rumors I've heard suggest that an updated outline algorithm is beginning to be implemented in a few browsers, and the updated algorithm prefers a new <h1> within each sectioning context, e.g. within each <section>, <article>, etc. But even so, it's not the predominate algorithm in the wild right now, so fair point, one <h1> per page.
How do you examine the generated outline for a page, as perceived by assistive tech? Are there good tools out there to help with this?
Yeah the spec calls for a new outline in each section, so multiple H1's are technically allowed, but assistive technologies and (as much as I hate this argument) SEO don't always line up with the spec. So for now it's safer to go the 1 H1 route.
Usually I use W3C's validator (validator.w3.org/nu) with the outline option checked to test for at least the basics.
Then there's some other tools (like the "Siteimprove Accessibility Checker" plugin for Chrome) that help a bunch as well (but they focus less on semantics and more on pure a11y).
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