$ git clone -n https://src.fedoraproject.org/rpms/gstreamermm.git /var/lib/mock/f29-build-6764-1666/root/thebuilddir/tmp/scmroot/gstreamermm
Cloning into '/var/lib/mock/f29-build-6764-1666/root/thebuilddir/tmp/scmroot/gstreamermm'...
$ git reset --hard c1bf47eff6050978876422b84b03dd4170842c58
HEAD is now at c1bf47e - Rebuilt for https://fedoraproject.org/wiki/Fedora_28_Mass_Rebuild