$ git clone -n https://src.fedoraproject.org/rpms/scmxx.git /var/lib/mock/f45-build-35661-698/root/chroot_tmpdir/scmroot/scmxx
Cloning into '/var/lib/mock/f45-build-35661-698/root/chroot_tmpdir/scmroot/scmxx'...
$ git fetch origin 1505a56ea9bd408b7485ae0608ff76b296ecfb0d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/scmxx
 * [new ref]         1505a56ea9bd408b7485ae0608ff76b296ecfb0d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1505a56 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild