A single word that is (already) known to git as being a valid command
to do --help with. I which case I fully agree.
Just to insist on "that is known to git as being a valid command".
Compare:
$ git foo --help
`git foo' is aliased to `bar'
with
$ git foo --help
No manual entry for gitbar
--
Matthieu Moy
http://www-verimag.imag.fr/~moy/