$ git clone -n https://src.fedoraproject.org/rpms/libtar.git /var/lib/mock/f45-build-17066-495/root/chroot_tmpdir/scmroot/libtar
Cloning into '/var/lib/mock/f45-build-17066-495/root/chroot_tmpdir/scmroot/libtar'...
$ git fetch origin c8b1a1732e7372f31980174e2b757f8a5f51d082:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libtar
 * [new ref]         c8b1a1732e7372f31980174e2b757f8a5f51d082 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c8b1a17 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild