I’ve been told about Mull and fennec, but what about:
(From what I understand)
- Firefox Focus: blocks trackers and erases browsing history
- Firefox Nightly: new updates every night
- Firefox Klar: german version of focus
- Iceraven Browser: 3rd party fork with more add ons
One of their partners in that region already established a brand under the same name.
From https://support.mozilla.org/en-US/kb/difference-between-firefox-focus-and-firefox-klar