Just came here to applaud this project and mention Teleparty (Chrome/Edge).
It is a collaborative video streaming service, on the top of most relevant lists on the internet. According to the Chrome web store it has "10,000,000+" users, on par with the likes of uBlock Origin (another amazing extension). Teleparty sadly does not seem to work here, although if any of you have had success I would love to hear.
I understand you have a lot of work on your hands but this might be another extension worth reviewing.