wpt/css/css-conditional/at-supports-043.html fails because of this bug.
<rdar://problem/68463401>
Safari is only browser failing this test case on WPT: https://wpt.fyi/results/css/css-conditional?label=master&label=experimental&aligned&view=subtest&q=at-supports-043
Odd. Blink has a change which says the opposite: https://github.com/chromium/chromium/commit/78e05d79151a74ce00905bd264987348b2d73a5d
*** This bug has been marked as a duplicate of bug 137568 ***