Created attachment 223879 [details] test case AX: invalidly nested columnheader role treated as UnknownRole This columnheader role is invalid outside the context of a grid, and should fall back to the default role for abbr, but WebKit treats it as UnknownRole. See test case.
<rdar://problem/16038457>
Tagging WPTImpact because this may fail with some of the impending role tests coming with the Interop 2023 Accessibility Investigation.