Gitのサブモジュール

[ Path: ~/.emacs.d (master) ]
$ git submodule add https://github.com/magit/magit.git lisp/magit
Cloning into lisp/magit...
remote: Counting objects: 5606, done.
remote: Compressing objects: 100% (2424/2424), done.
remote: Total 5606 (delta 3511), reused 5207 (delta 3142)
Receiving objects: 100% (5606/5606), 1.27 MiB | 306 KiB/s, done.
Resolving deltas: 100% (3511/3511), done.