$ git clone -n https://src.fedoraproject.org/rpms/ocaml-lwt.git /var/lib/mock/f40-build-784458-133438/root/chroot_tmpdir/scmroot/ocaml-lwt
Cloning into '/var/lib/mock/f40-build-784458-133438/root/chroot_tmpdir/scmroot/ocaml-lwt'...
$ git fetch origin e431299a442f7c2bd141f8028886ff4e255abb68:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ocaml-lwt
 * [new ref]         e431299a442f7c2bd141f8028886ff4e255abb68 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e431299 Bump and rebuild