$ git clone -n https://src.fedoraproject.org/rpms/ocaml-ppx-deriving-yaml.git /var/lib/mock/f42-build-side-1-3517006-46096/root/chroot_tmpdir/scmroot/ocaml-ppx-deriving-yaml
Cloning into '/var/lib/mock/f42-build-side-1-3517006-46096/root/chroot_tmpdir/scmroot/ocaml-ppx-deriving-yaml'...
$ git fetch origin 7b781714151d3f8a98b63287b925ec4fe50faab9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ocaml-ppx-deriving-yaml
 * [new ref]         7b781714151d3f8a98b63287b925ec4fe50faab9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7b78171 Rebuild for ocaml-ppxlib 0.35.0