It seems like StereoEffect was added back in the days before the WebVR/AR/XR existed and was intended for use with old VR products like Google Cardboard.
I’m searching around on GitHub but not finding many clues - has StereoEffect been completely replaced by the WebVR stuff? Or are there still situations in which you would want to use it?
It might be obsolete in XR scenarios but I think it is still useful if people want to create a simple/funny stereo effect for their app. It also has an educational purpose because it shows the minimal setup that is necessary for stereo rendering. Since the code is straightforward, I would keep it in the repo.
Yes, a note in the documentation might be useful to clarify things. But I guess I would write it less as a warning^^. And refer to the VR guide instead. Something like: