$ git clone -n https://src.fedoraproject.org/rpms/libmng.git /var/lib/mock/f31-build-71829-30332/root/thebuilddir/tmp/scmroot/libmng
Cloning into '/var/lib/mock/f31-build-71829-30332/root/thebuilddir/tmp/scmroot/libmng'...
$ git reset --hard 3a99891602f766c02e95c62567f4c2077c67c20b
HEAD is now at 3a99891 - Rebuilt for https://fedoraproject.org/wiki/Fedora_31_Mass_Rebuild