$ git clone -n https://src.fedoraproject.org/rpms/tart.git /var/lib/mock/f40-build-771260-125945/root/chroot_tmpdir/scmroot/tart
Cloning into '/var/lib/mock/f40-build-771260-125945/root/chroot_tmpdir/scmroot/tart'...
$ git fetch origin a4b45c0e54c622fd72a09d4471951fa3398c43c6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/tart
 * [new ref]         a4b45c0e54c622fd72a09d4471951fa3398c43c6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a4b45c0 bump release