$ git clone -n https://src.fedoraproject.org/rpms/xboard.git /var/lib/mock/f45-build-38623-726/root/chroot_tmpdir/scmroot/xboard
Cloning into '/var/lib/mock/f45-build-38623-726/root/chroot_tmpdir/scmroot/xboard'...
$ git fetch origin 3aeba8fcf524a48c94948dcfcd3c4d5d44d8caf1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/xboard
 * [new ref]         3aeba8fcf524a48c94948dcfcd3c4d5d44d8caf1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3aeba8f Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild