$ git clone -n https://src.fedoraproject.org/rpms/ocaml-bos.git /var/lib/mock/f40-build-768300-125260/root/chroot_tmpdir/scmroot/ocaml-bos
Cloning into '/var/lib/mock/f40-build-768300-125260/root/chroot_tmpdir/scmroot/ocaml-bos'...
$ git fetch origin 0ba46a8d46e9a49401444ed50a198c26ef6500e4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ocaml-bos
 * [new ref]         0ba46a8d46e9a49401444ed50a198c26ef6500e4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0ba46a8 Bump release and rebuild