You can use it today with these values. If you have any feedback/questions I would love to hear.
URL: https://g.webrtc.live-video.net:4443/v2/offer
Bearer Token: (Twitch Stream Key)
You can stream from your browser or from other tools like OBS. You can get a build of OBS that supports WebRTC here. https://github.com/obsproject/obs-studio/pull/7926. This doesn't use all the features of WebRTC yet, but it will continue getting better and better.