$ git clone -n https://src.fedoraproject.org/rpms/ocaml-tyxml.git /var/lib/mock/f42-build-3364225-45044/root/chroot_tmpdir/scmroot/ocaml-tyxml
Cloning into '/var/lib/mock/f42-build-3364225-45044/root/chroot_tmpdir/scmroot/ocaml-tyxml'...
$ git fetch origin 5aeddefefdbc2127c8b4f111f1f95decd96b192e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ocaml-tyxml
 * [new ref]         5aeddefefdbc2127c8b4f111f1f95decd96b192e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5aeddef Rebuild for ocaml-ppxlib 0.35.0