Librewolf is a fork of Firefox.

From their site:

LibreWolf also aims to remove all the telemetry, data collection and annoyances, as well as disabling anti-freedom features like DRM.

In the future, Ladybird or a browser built on top of Servo might be alternatives, but both projects are pretty far from being usable right now.

Mozilla says that “there are a number of places where we collect and share some data with our partners” so that Firefox can be “commercially viable,” but it adds that it spells those out in its privacy notice and works to strip data of potentially identifying information or share it in aggregate.

Sounds like they’ve already been selling (or trading) data and this whole debacle is a way to retroactively cover their asses.