$ git clone -n https://src.fedoraproject.org/rpms/R-base64enc.git /var/lib/mock/f29-build-1121-469/root/thebuilddir/tmp/scmroot/R-base64enc
Cloning into '/var/lib/mock/f29-build-1121-469/root/thebuilddir/tmp/scmroot/R-base64enc'...
$ git reset --hard 170e1f6bf18821876d33c769320f1f2f9c6aebca
HEAD is now at 170e1f6 - Rebuilt for https://fedoraproject.org/wiki/Fedora_28_Mass_Rebuild