$ git clone -n https://src.fedoraproject.org/rpms/ghc-unix-compat.git /var/lib/mock/f41-build-837890-159471/root/chroot_tmpdir/scmroot/ghc-unix-compat
Cloning into '/var/lib/mock/f41-build-837890-159471/root/chroot_tmpdir/scmroot/ghc-unix-compat'...
$ git fetch origin 6b939c90e8e614ab022a3de340d787933698f533:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-unix-compat
 * [new ref]         6b939c90e8e614ab022a3de340d787933698f533 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6b939c9 https://hackage.haskell.org/package/unix-compat-0.7.2/changelog