Question on determining whether aria-labelledby maps to AXDescription or AXTitle

[sivakusayan]

The current mapping states that browsers should expose aria-labelledby through AXTitle if the value is rendered visually. However, if I'm reading WebKit's AXDescription code right, it will always expose aria-labelledby via AXDescription. Very briefly going over this WPT page with the Mac accessibility inspector seems to confirm my hypothesis (for buttons, anyway). Webkit's AXTitle code seems to be mostly used to expose name from content and HTML labels.

I think it would be nice to get some clarification of whether we should be following WebKit or the spec here - this discrepancy makes me unsure how to fix this Chromium bug where a dialog's title isn't read when focus moves into the dialog. This happens because VoiceOver (tested on Ventura 13.5) won't respect a dialog's AXTitle if AXTitleUIElement is null, but I'm not sure if we can guarantee that AXTitleUIElement always exists (for example, if aria-labelledby points to two nodes). Safari gets past this by exposing the dialog's title through AXDescription.

[aleventhal]

@cookiecrook can you give guidance so that we can fix the Chromium bug? Thanks!