$ git clone -n https://src.fedoraproject.org/rpms/ghc-deepseq-generics.git /var/lib/mock/f40-build-1997865-44187/root/chroot_tmpdir/scmroot/ghc-deepseq-generics
Cloning into '/var/lib/mock/f40-build-1997865-44187/root/chroot_tmpdir/scmroot/ghc-deepseq-generics'...
$ git fetch origin 3f17fcae1ef94aa20ac968d6d00916d9b94ada0e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-deepseq-generics
 * [new ref]         3f17fcae1ef94aa20ac968d6d00916d9b94ada0e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3f17fca revised .cabal file