$ git clone -n https://src.fedoraproject.org/rpms/ghc-scientific.git /var/lib/mock/f40-build-742449-110760/root/chroot_tmpdir/scmroot/ghc-scientific
Cloning into '/var/lib/mock/f40-build-742449-110760/root/chroot_tmpdir/scmroot/ghc-scientific'...
$ git fetch origin 8d71a68a37d9a9a1a3492c6428c7c7d9f54d1fe8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-scientific
 * [new ref]         8d71a68a37d9a9a1a3492c6428c7c7d9f54d1fe8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8d71a68 revised .cabal file