- Why is the flag considered a request which may be ignored?
- Why are you incapable of inspecting or controlling the applied quality level of MSAA?
- Why are you incapable of checking if the request has been satisfied?
At the very least, WebGL developers should have the ability to detect whether antialiasing can actually be applied and to what degree.
That is, how many color/depth/stencil samples, how many coverage samples, etc. That way, if the native implementation is insufficient, they can replace it with a custom post-processing filter, possibly in combination with super-resolution rendering. I could easily see myself doing a quick off-screen rendering benchmark to determine optimal settings. Right now I can't, because I'm working blind.