-This simply creates an empty git object database - basically a `.git`
-directory and `.git/object/??/` directories.
+This simply creates an empty git repository - basically a `.git` directory
+and `.git/object/??/`, `.git/refs/heads` and `.git/refs/tags` directories,
+and links `.git/HEAD` symbolically to `.git/refs/heads/master`.
+
+If the 'GIT_DIR' environment variable is set then it specifies a path
+to use instead of `./.git` for the base of the repository.