$ git clone -n https://src.fedoraproject.org/rpms/ghc-th-orphans.git /var/lib/mock/f41-build-839600-160255/root/chroot_tmpdir/scmroot/ghc-th-orphans
Cloning into '/var/lib/mock/f41-build-839600-160255/root/chroot_tmpdir/scmroot/ghc-th-orphans'...
$ git fetch origin d9dcc1b21c280a82114238f82b4bc5404bc48e2e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-th-orphans
 * [new ref]         d9dcc1b21c280a82114238f82b4bc5404bc48e2e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d9dcc1b revise .cabal file