$ git clone -n https://src.fedoraproject.org/rpms/ocaml-ppx-deriving.git /var/lib/mock/f40-build-784286-133348/root/chroot_tmpdir/scmroot/ocaml-ppx-deriving
Cloning into '/var/lib/mock/f40-build-784286-133348/root/chroot_tmpdir/scmroot/ocaml-ppx-deriving'...
$ git fetch origin 15a89da86f65fcf79b1ade65f7c6c406cabe5747:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ocaml-ppx-deriving
 * [new ref]         15a89da86f65fcf79b1ade65f7c6c406cabe5747 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 15a89da Rebuild for changed ocamlx hashes