I don't understand why this is news?
Spyware watchdog posted about this years ago. It's been in there at least since 2016, and every time you open Firefox (not start!) it will happily broadcast its geo position information to their geolocation backend. The same goes for the WebRTC related STUN servers, which are always connected to when Firefox starts.
I mean, come on folks. Never trust any software blindly. Use MITM proxy to verify. Use a host firewall like opensnitch.
For the moment the best alternative is ungoogled chromium with ublock origin, even though the CSP headers cannot influence the DNS resolver mechanics in the CEF code.
I am still busy forking webkit into retrokit and it's a shitload of work to remove these tracking features. [1] But a project like this needs more privacy like minded people.
I mean, even the TOR people kind of gave up on this. Just look at their codebase, trying to stub everything anew with upstream changes.
There's no point in trying to race against chrome in "whose browser has the most features", you can't win anyways. I don't care about WebGL or WebGPU, I don't care about WebRTC, I just want privacy back.