Emacs comes with
log-edit.el a mode for editing commit messages for various version control systems. It is used by VersionControl.
It appears that not every Git user was aware of its existence or wanted to write another mode from scratch for some other reason. So various implementations of
git-commit.elcan be found here.
git-commit-mode.el, and bundled it with some other git-related libraries and called the resulting repository
git-modes. While these libraries live in the same repository, they are available as separate packages from Melpa.
magit-log-edit.el. The former name was used for the merged mode,which remains in the
git-modesrepository (which has been moved to magit/git-modes), and Jonas became its new maintainer.
magit-log-edit.elwas removed from Magit.
git-commit.elwas moved from the
git-modesrepository to the