$ git clone -n https://src.fedoraproject.org/rpms/ocaml-yaml.git /var/lib/mock/f41-build-843768-162105/root/chroot_tmpdir/scmroot/ocaml-yaml
Cloning into '/var/lib/mock/f41-build-843768-162105/root/chroot_tmpdir/scmroot/ocaml-yaml'...
$ git fetch origin b6fd9e9df270bd6831e816b6777f14ed1b7170e6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ocaml-yaml
 * [new ref]         b6fd9e9df270bd6831e816b6777f14ed1b7170e6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b6fd9e9 Rebuild for ocaml-ctypes 0.23.0