</para>
        </callout>
        <callout arearefs='ex-hello-co-tarball-args'>
          <para>
            The <varname>tarball</varname> jobs expects a
            <varname>hello</varname> build input to be available in the
            Nix search path.  Again, this input is passed by Hydra and
            is meant to be a checkout of GNU Hello's source code
            repository.

        <callout arearefs='ex-hello-co-tarball-args'>
          <para>
            The <varname>tarball</varname> jobs expects a
            <varname>hello</varname> build input to be available in the
            Nix search path.  Again, this input is passed by Hydra and
            is meant to be a checkout of GNU Hello's source code
            repository.
          </para>
        </callout>