Interesting! A few years ago I started a similar project, essentially a clearnet fork of Tor called Aegis. Problem was, it makes a lot of the modern web very broken. A very niche corner of the web browser market - but a lot of things like WebRTC and Widevine (unfortunately) are what most users would expect. I'd imagine there's the possibility there will be no H264 support either?

Nice to see more Firefox related forks though, hopefully help gain more ground on the web for alternative engines.