code: def default(cls):
      
      if cls._DEFAULT is None:
        cls._DEFAULT = cls.skip_signatures_and_duplicates_concat_well_known_metadata()
      return cls._DEFAULT
docs: Returns the default set of jar rules.
  
      Can be set with `set_default` but otherwise defaults to
      `skip_signatures_and_duplicates_concat_well_known_metadata`.
  
      :API: public