$ git clone -n https://src.fedoraproject.org/rpms/ghc-temporary.git /var/lib/mock/f31-build-84142-31568/root/thebuilddir/tmp/scmroot/ghc-temporary
Cloning into '/var/lib/mock/f31-build-84142-31568/root/thebuilddir/tmp/scmroot/ghc-temporary'...
$ git reset --hard 924c16bc8f09e8d45cc26de318b4592fccc29515
HEAD is now at 924c16b - Rebuilt for https://fedoraproject.org/wiki/Fedora_31_Mass_Rebuild