Yes. ~/.mozilla. Its annoying.
You can fix it with a hack by putting a shell script in your path (before the original firefox) that consist of:
#!/bin/sh
HOME='/home/engywuck/.local/share/firefox' /usr/bin/firefox
Call that instead of the original firefox from now on. it will create the “librewolf” folder in ~/.local/share and chuck its junk in there.
Edit: This bug has been open for TWENTY YEARS.
Honestly ridiculous.
Linus already has a backup. Its Greg Kroah-Hartman.