The font-family-rule-011 test fails. http://www.w3.org/TR/CSS21/fonts.html#font-family-prop Note the words in the spec: "The keywords 'initial' and 'default' are reserved for future use and must also be quoted when used as font names. UAs must not consider these keywords as matching the '<family-name>' type."
https://wpt.fyi/results/css/CSS2/fonts?label=master&label=experimental&aligned&view=subtest&q=font-family-rule It is not WPT. Do we follow WPT only test for CSS2 or we do follow CSS2 original test suite? Test Link - http://test.csswg.org/suites/css21_dev/20110323/xhtml1/font-style-rule-001.xht
WPT is certainly not the source of truth in any way, but this test is on wpt.live: http://wpt.live/css/CSS2/fonts/font-family-rule-011.xht (note that it's "011", not "001" as above). That said, the test is fundamentally broken, because it relies on a "default" font being installed in the OS, which no one has, and Safari wouldn't use anyway (we only expose a fixed set of fonts, to reduce fingerprinting). Simon, do you remember how you observed the failure? Is this still actionable?