See https://github.com/w3c/csswg-drafts/issues/7832 resolution https://phabricator.services.mozilla.com/D164128 for mozilla change.
<rdar://problem/103119662>
Pull request: https://github.com/WebKit/WebKit/pull/7510
Committed 257772@main (cf0f5ed10f29): <https://commits.webkit.org/257772@main> Reviewed commits have been landed. Closing PR #7510 and removing active labels.