See https://www.w3.org/TR/css-fonts-4/#valdef-font-family-math https://mathml-refresh.github.io/mathml-core/#the-top-level-math-element
By updating mathml.css, we do start passing following test case: math { font-family: math; } https://github.com/WebKit/WebKit/blob/d265fb0d526aa8120a208bf62dc5a1e160400cc7/Source/WebCore/css/mathml.css#L72 >>> http://wpt.live/mathml/relations/css-styling/default-font-family.html Although I don't know whether we have more to do here or not but still just wanted to flag.