code: def ls(system, user, local, include_missing):
      
  
      # default action is to list *all* auto-detected files
      if not (system or user or local):
          system = user = local = True
  
      for path in get_configfile_paths(system=system, user=user, local=local,
                                       only_existing=not include_missing):
          click.echo(path)
docs: List configuration files detected (and/or examined paths).