$ git clone -n https://src.fedoraproject.org/rpms/ghc-io-streams.git /var/lib/mock/f40-build-744404-111705/root/chroot_tmpdir/scmroot/ghc-io-streams
Cloning into '/var/lib/mock/f40-build-744404-111705/root/chroot_tmpdir/scmroot/ghc-io-streams'...
$ git fetch origin 13b89bc214c3f8ba4c56392c06c4aed8d8d4fa13:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-io-streams
 * [new ref]         13b89bc214c3f8ba4c56392c06c4aed8d8d4fa13 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 13b89bc revised .cabal file