$ git clone -n https://src.fedoraproject.org/rpms/ocaml-ppx-deriving-yaml.git /var/lib/mock/f40-build-784491-133438/root/chroot_tmpdir/scmroot/ocaml-ppx-deriving-yaml
Cloning into '/var/lib/mock/f40-build-784491-133438/root/chroot_tmpdir/scmroot/ocaml-ppx-deriving-yaml'...
$ git fetch origin db9b4ead2d4b03bb505bda56a02b3f0d0186dc18:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ocaml-ppx-deriving-yaml
 * [new ref]         db9b4ead2d4b03bb505bda56a02b3f0d0186dc18 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at db9b4ea Rebuild for changed ocamlx hashes