$ git clone -n https://src.fedoraproject.org/rpms/cmatrix.git /var/lib/mock/f31-build-57129-28299/root/chroot_tmpdir/scmroot/cmatrix
Cloning into '/var/lib/mock/f31-build-57129-28299/root/chroot_tmpdir/scmroot/cmatrix'...
$ git reset --hard 778c678b2330b3a66e613ee2b8de10bbebe43cda
HEAD is now at 778c678 - Rebuilt for https://fedoraproject.org/wiki/Fedora_30_Mass_Rebuild