Firefox has telemetry and has become adware. Mozilla VPN ads pop up every once in a while. Sponsored bullshit on the home screen. Pocket integration with recommended/sponsored content. Mozilla's becoming what it set out to destroy unfortunately.

LibreWolf is Firefox without this garbage, plus more privacy focused defaults. Some of those defaults are rather extreme though so I recommend toning it back (such as deleting history/cookies after every session, and resist fingerprinting can screw up anything that displays time by not taking your time zone into account).