$ git clone -n https://src.fedoraproject.org/rpms/ghc-language-docker.git /var/lib/mock/f41-build-839506-160201/root/chroot_tmpdir/scmroot/ghc-language-docker
Cloning into '/var/lib/mock/f41-build-839506-160201/root/chroot_tmpdir/scmroot/ghc-language-docker'...
$ git fetch origin 815be1d5c0aa855bdd9dc31c3d3f8b6a0454b8ce:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-language-docker
 * [new ref]         815be1d5c0aa855bdd9dc31c3d3f8b6a0454b8ce -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 815be1d https://hackage.haskell.org/package/language-docker-12.1.0/changelog