$ git clone -n https://src.fedoraproject.org/rpms/ocaml-ppx-optcomp.git /var/lib/mock/f40-build-784013-133240/root/chroot_tmpdir/scmroot/ocaml-ppx-optcomp
Cloning into '/var/lib/mock/f40-build-784013-133240/root/chroot_tmpdir/scmroot/ocaml-ppx-optcomp'...
$ git fetch origin 030c9fdbd6cb61db802dd7986084aa5f0d7b860c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ocaml-ppx-optcomp
 * [new ref]         030c9fdbd6cb61db802dd7986084aa5f0d7b860c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 030c9fd Rebuild for changed ocamlx hashes