code: def _create_main_config(cls, overrides=None):
          
          filepaths = []
          filepaths.append(get_module_root_config())
          filepath = os.getenv("REZ_CONFIG_FILE")
          if filepath:
              filepaths.extend(filepath.split(os.pathsep))
  
          filepath = os.path.expanduser("~/.rezconfig")
          filepaths.append(filepath)
  
          return Config(filepaths, overrides)
docs: See comment block at top of 'rezconfig' describing how the main
          config is assembled.