$ git clone -n https://src.fedoraproject.org/rpms/ocaml-rresult.git /var/lib/mock/f40-build-784045-133248/root/chroot_tmpdir/scmroot/ocaml-rresult
Cloning into '/var/lib/mock/f40-build-784045-133248/root/chroot_tmpdir/scmroot/ocaml-rresult'...
$ git fetch origin 530b00e5514ba6b98bebb40a25deb109b6ccceb6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ocaml-rresult
 * [new ref]         530b00e5514ba6b98bebb40a25deb109b6ccceb6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 530b00e Bump and rebuild