anchor.diff:  
         knownHosts = mkOption {
           default = {};
  -        type = types.loaOf (types.submodule {
  +        type = types.loaOf (types.submodule ({ name, ... }: {
             options = {
               hostNames = mkOption {
                 type = types.listOf types.str;
  
positive.code:   knownHosts = map (h: getAttr h cfg.knownHosts) (attrNames cfg.knownHosts);
  
    knownHostsText = flip (concatMapStringsSep "\n") knownHosts
      (h:
        concatStringsSep "," h.hostNames + " "
        + (if h.publicKey != null then h.publicKey else readFile h.publicKeyFile)
      );
  
negative.code:               '';
              };
            };
            config = {
              hostNames = mkDefault [ name ];
            };
          }));
          description = ''
            The set of system-wide known SSH hosts.
          '';
  