[mwcampbell]

Yes, that's true today. But since they're running a version of Chromium that they control, they can in principle modify it to push semantic information from the Chromium accessibility implementation along with the video stream. That would be much harder for, say, Zoom screen sharing to do, because of the way the platform accessibility APIs are designed.

[unfocussed_mike]

Ahh -- I see. Informative answer, thank you :-)