Fredrik Gustafsson [off-list ref] writes:
Check if [path] is a valid git-dir or a valid git-file that points
to a valid git-dir.
On Subject, here, and in the doc, I do not think you meant "[path]" (which
typically means "you do not have to have anything, but you are allowed to
have a path, if you do write something here."). Perhaps you meant to say
<path> instead (which is how most if not all of the documentation mark a
placeholder in a description)?