The "MathML Acid2 Test" fails to render properly in WebKit. Attached is a screenshot showing the result in a recent WebKitGTK+ release.
Created attachment 200517 [details]
Screenshot of failed rendering
Most of the elements used in this test are elements that should be invisible (like the semantics tag used by people generating math with annotations) or elements allowing to modify the spacing of formulas (used by many TeX-to-MathML converters). I don't think it should be too hard to implement them.
Personally I think the stretchy operator code and operator dictionary is of higher priority at the moment.
For invisible elements (semantics, maction, mphantom), the MathML for CSS profile used by Opera could be helpful:
I don't have the edit bugzilla rights, but this also depends on bug 100626.
I don't see all of those error states when I try this today. Is this now working properly?
I think the result is better than in the screenshot, but it will only pass when the three open "depends on" bugs are fixed.