anchor.diff:        type = types.bool;
         default = !config.boot.isContainer;
         description = ''
  -        Whether to enable support for NixOS containers.
  +        Whether to enable support for NixOS containers. Defaults to true
  +        (at no cost if containers are not actually used), but only if the
  +        system is not itself a lightweight container of a host.
  +        To enable support for nested containers, this option has to be
  +        explicitly set to true (in the outer container).
         '';
       };
   
  
positive.code:               type = with types; attrsOf (submodule { options = networkOptions; });
                default = {};
                description = ''
                  Extra veth-pairs to be created for the container
                '';
              };
  
  
negative.code:       default = false;
        description = ''
          Whether this NixOS machine is a lightweight container running
          in another NixOS system. If set to true, support for nested
          containers is disabled by default, but can be reenabled by
          setting <config>boot.enableContainers</config> to true.
        '';
      };
  
  