TL;DR: With Firefox 56, Mozilla combined Firefox Health Report and Telemetry data into a single setting called “technical and interaction data”, which was then enabled by default. This data was then shared with advertising partners on a de-identified or aggregated basis.
How does Librewolf improve on this?
It specifically removes all of Mozilla’s telemetry.
Good.
Tor Browser and Mullvad browser also do this.
So does Icecat and it even cuts out sync as well, where LibreWolf leaves it in and disables it by default, leaving it up to the user to enable at their leisure.
I really, really want to use Librewolf. I’m on WaterFox until they have a binary build available that doesn’t fail MacOS security checks on launch.