$ git clone -n https://src.fedoraproject.org/rpms/gtkmm30.git /var/lib/mock/f31-build-85982-31646/root/chroot_tmpdir/scmroot/gtkmm30
Cloning into '/var/lib/mock/f31-build-85982-31646/root/chroot_tmpdir/scmroot/gtkmm30'...
$ git reset --hard de4075547ceaf110ae98472412618595cbbf6a79
HEAD is now at de40755 - Rebuilt for https://fedoraproject.org/wiki/Fedora_31_Mass_Rebuild