$ git clone -n https://src.fedoraproject.org/rpms/rubygem-aruba.git /var/lib/mock/f39-build-1655489-40540/root/chroot_tmpdir/scmroot/rubygem-aruba
Cloning into '/var/lib/mock/f39-build-1655489-40540/root/chroot_tmpdir/scmroot/rubygem-aruba'...
$ git fetch origin 65f279cdeb3d4537cdf832417ca2e03b77e5f786:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-aruba
 * [new ref]         65f279cdeb3d4537cdf832417ca2e03b77e5f786 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 65f279c 2.2.0