$ git clone -n https://src.fedoraproject.org/rpms/kstars.git /var/lib/mock/f39-build-1768341-41501/root/chroot_tmpdir/scmroot/kstars
Cloning into '/var/lib/mock/f39-build-1768341-41501/root/chroot_tmpdir/scmroot/kstars'...
$ git fetch origin 5711a0b91cdaecb620dc24105a676016a78ae1e0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/kstars
 * [new ref]         5711a0b91cdaecb620dc24105a676016a78ae1e0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5711a0b Update to 3.6.6