I'm opening this for the record. In the long term when modern math fonts are widespread, we want to get rid of - Obsolete math fonts from the font-family list of the math tag in mathml.css - Radical drawing with strokePath - Stretching of vertical operators using Unicode-only characters instead of the MathVariants table. See http://trac.webkit.org/wiki/MathML/Fonts#ObsoleteFontsandFallbackMechanisms