$ git clone -n https://src.fedoraproject.org/rpms/ghc-servant-server.git /var/lib/mock/f41-build-side-1-2883163-34500/root/chroot_tmpdir/scmroot/ghc-servant-server
Cloning into '/var/lib/mock/f41-build-side-1-2883163-34500/root/chroot_tmpdir/scmroot/ghc-servant-server'...
$ git fetch origin e7af0d8ba2ef21491d8e527d5d05788d6ecbb11b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-servant-server
 * [new ref]         e7af0d8ba2ef21491d8e527d5d05788d6ecbb11b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e7af0d8 https://hackage.haskell.org/package/servant-server-0.20/changelog