See https://github.com/whatwg/html/pull/9121.
Pull request: https://github.com/WebKit/WebKit/pull/13362
Committed 263749@main (db3c1dec69db): <https://commits.webkit.org/263749@main> Reviewed commits have been landed. Closing PR #13362 and removing active labels.
<rdar://problem/108981765>
Did the new WPT in this patch ever get synced upstream?