$ git clone -n https://src.fedoraproject.org/rpms/R-Cairo.git /var/lib/mock/f29-build-1034-455/root/thebuilddir/tmp/scmroot/R-Cairo
Cloning into '/var/lib/mock/f29-build-1034-455/root/thebuilddir/tmp/scmroot/R-Cairo'...
$ git reset --hard f54930e8c29c2f7a4ecb62d549232e90b00c737e
HEAD is now at f54930e - Rebuilt for https://fedoraproject.org/wiki/Fedora_28_Mass_Rebuild