We already support `format()` in `@font-face src` so `font-format()` should be trivial to add.
<rdar://problem/107381176>
Pull request: https://github.com/WebKit/WebKit/pull/12133
Committed 262305@main (c80f8136b208): <https://commits.webkit.org/262305@main> Reviewed commits have been landed. Closing PR #12133 and removing active labels.