This is covered by web-platform-tests/css/css-fonts/font-face-range-order.html font-face must accept ranges in reverse order, and reverse them for *computed* style.
<rdar://problem/101210777>
Pull request: https://github.com/WebKit/WebKit/pull/5427
Committed 255893@main (30bf0f961d69): <https://commits.webkit.org/255893@main> Reviewed commits have been landed. Closing PR #5427 and removing active labels.