We are about to ship support for :is() and :where() in Chromium, including support for <forgiving-selector-list>. As far as I understand, :is() in Safari 14 takes a regular <selector-list>, and Chromium API owners are concerned that this is a potential source of interop problems.

Are there any plans to implement the <forgiving-selector-list> behavior in WebKit as well?

Thanks,

Anders

FYI: https://bugs.webkit.org/show_bug.cgi?id=217814