$ git clone -n https://src.fedoraproject.org/rpms/ghc-ghc-mtl.git /var/lib/mock/f31-build-54374-27995/root/chroot_tmpdir/scmroot/ghc-ghc-mtl
Cloning into '/var/lib/mock/f31-build-54374-27995/root/chroot_tmpdir/scmroot/ghc-ghc-mtl'...
$ git reset --hard 935aab2d79010380b7a692a91a9f6813c0a2036a
HEAD is now at 935aab2 refresh to cabal-rpm-0.13