$ git clone -n https://src.fedoraproject.org/rpms/gmp-ecm.git /var/lib/mock/f29-build-2447-725/root/thebuilddir/tmp/scmroot/gmp-ecm
Cloning into '/var/lib/mock/f29-build-2447-725/root/thebuilddir/tmp/scmroot/gmp-ecm'...
$ git reset --hard 5f6011835397fa97de61734d478d99e36ace521a
HEAD is now at 5f60118 - Rebuilt for https://fedoraproject.org/wiki/Fedora_28_Mass_Rebuild