@publicvoit Sorta weird question, even GNU Emacs is a niche.
But you have CLIMACS, Hemlock, you have ersatz emacs like mg. In the "back from the future" world you got ZWEI. In the proprietary world, Lispworks has a fork of Zwei.
GNU Emacs is the best Emacs, but Emacs is just an editor -- with a specific UX.
I think it is a mistake to equate e.g., Magit and Emacs -- they both run under GNU Emacs but they are very different in how they work.