Maybe it's sort of ponyfill?

This is absolutely normal. A <div> by itself means nothing without ARIA attributes. It won't even appear in the accessibility tree, and assistive technologies won't know about it.

Sometimes I think native HTML, CSS and JS turn into a low-level Assembler language for the Web that is the result of compiling a high-level framework language. And only a11y/perf experts really know this low-level web stack.

Oh, third-party hell from Tag Manager always drastically worsens Lighthouse scores, even if they were initially good

<div> is not a <button> 19-hours version

There is a bookmarklet that is offered for testing 1.4.12. It uses relative em units to change text parameters. So font size in the context of 1.4.12 refers to the CSS font-size property

www.html5accessibility.com/tests/tsbook...

Yeah, I'm interested

I wonder why the already existing selector ::part(name) is not used and instead pseudo elements are created for each new case (::details-content, ::picker(select)). After all, the customizable select works as a system web component

XSLT vibes