$ git clone -n https://src.fedoraproject.org/rpms/ghc-HTTP.git /var/lib/mock/f40-build-743767-111387/root/chroot_tmpdir/scmroot/ghc-HTTP
Cloning into '/var/lib/mock/f40-build-743767-111387/root/chroot_tmpdir/scmroot/ghc-HTTP'...
$ git fetch origin 271417239afae2a1c39dd4121690c5f81252f3f2:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-HTTP
 * [new ref]         271417239afae2a1c39dd4121690c5f81252f3f2 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2714172 revised .cabal file