$ git clone -n https://src.fedoraproject.org/rpms/rubygem-clutter-gstreamer.git /var/lib/mock/f40-build-732382-13186/root/chroot_tmpdir/scmroot/rubygem-clutter-gstreamer
Cloning into '/var/lib/mock/f40-build-732382-13186/root/chroot_tmpdir/scmroot/rubygem-clutter-gstreamer'...
$ git fetch origin 6f6a354c6b0a827c6a42e19670b41df0152e2391:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-clutter-gstreamer
 * [new ref]         6f6a354c6b0a827c6a42e19670b41df0152e2391 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6f6a354 4.2.2 entry