In bug 113720, an attribute NSAccessibilityMathLineThicknessAttribute was added to AXMathFraction to help distinguishing fractions that have a bar or not. Compare data:text/html,<math><mrow><mo>(</mo><mfrac><mi>a</mi><mi>p</mi></mfrac><mo>)</mo></mrow></math> (https://en.wikipedia.org/wiki/Legendre_symbol) with data:text/html,<math><mrow><mo>(</mo><mfrac linethickness="0px"><mi>n</mi><mi>k</mi></mfrac><mo>)</mo></mrow></math> (https://en.wikipedia.org/wiki/Combination) However, VoiceOver does not distinguish the two cases, it always read "fraction start ... over ... end of fraction". I think it should instead read the one with linethickness="0px" as "fraction without bar start ... over ... end of fraction", "stack start ... over .. end of stack" or something similar.
<rdar://problem/21609197>
This problem appears in tests 8 and 9 of the MathML torture test: https://mdn.mozillademos.org/en-US/docs/Mozilla/Math-ML_Project/MathML_Torture_Test$samples/MathML_Torture_Test
The fix for this issue was needed outside the WebKit project, therefore this is being resolved as 'Moved'. This should now be fixed in shipping software.