$ git clone -n https://src.fedoraproject.org/rpms/rubygem-pg.git /var/lib/mock/f31-build-52764-27742/root/thebuilddir/tmp/scmroot/rubygem-pg
Cloning into '/var/lib/mock/f31-build-52764-27742/root/thebuilddir/tmp/scmroot/rubygem-pg'...
$ git reset --hard 878f0a9c48f42f85b7dcaf127dd8b2c2f08ff7b9
HEAD is now at 878f0a9 - Rebuilt for https://fedoraproject.org/wiki/Fedora_30_Mass_Rebuild