Firefox

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

Klar by Firefox is the German-language version and only available in Germany, Austria, and Switzerland. It includes the same features as the English-language app Focus by Firefox.

Why did we change the name/replace the app?

The publishing and media company Burda, which the news magazine FOCUS belongs to in Germany, is one of our partners. We therefore decided to replace our app "Focus by Firefox" in Germany, Austria, and Switzerland by "Klar by Firefox".

If you think it is suspicious you should be able to spot it in the open source repository. Otherwise see the other, and probably only, reason for the different name.

Just the name is different, since a german news magazine already claims the name "fokus". Mozilla was forced to rename its browser because of that