Does it mean the OS is volunteering the information that something is tapping into the framebuffer? Can that be disabled to render the browser clueless?
Same can happen with Chrome + Google Meet + OBS Studio btw.
AFAIK, the OS provides this information and, at least on Windows, you can't circumvent it easily. I was told it is one of these things that large content providers demand.
I am curious how it works on Linux.