$ git clone -n https://src.fedoraproject.org/rpms/xbiso.git /var/lib/mock/f45-build-38615-726/root/chroot_tmpdir/scmroot/xbiso
Cloning into '/var/lib/mock/f45-build-38615-726/root/chroot_tmpdir/scmroot/xbiso'...
$ git fetch origin 574bd0e90b89b85ceffbbf26a670809ad63e8751:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/xbiso
 * [new ref]         574bd0e90b89b85ceffbbf26a670809ad63e8751 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 574bd0e Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild