There are a fair few new tests in that suite and we should update it before we start working on implementing some of the newer CSS Animations properties (such as animation-timeline).
Pull request: https://github.com/WebKit/WebKit/pull/19707
Committed 269974@main (2ed0a830c2f7): <https://commits.webkit.org/269974@main> Reviewed commits have been landed. Closing PR #19707 and removing active labels.
<rdar://problem/117704042>