$ git clone -n https://src.fedoraproject.org/rpms/filesystem.git /var/lib/mock/f31-build-66821-29946/root/thebuilddir/tmp/scmroot/filesystem
Cloning into '/var/lib/mock/f31-build-66821-29946/root/thebuilddir/tmp/scmroot/filesystem'...
$ git reset --hard 339ac8220c88eafcb26ae42a031822e46f8c8cba
HEAD is now at 339ac82 - Rebuilt for https://fedoraproject.org/wiki/Fedora_31_Mass_Rebuild