docs: def preferred_encodings(self):
          """
          The list of user defined encodings, for display in the encodings
          menu/combobox.
  
          """
          default_encodings = [
              locale.getpreferredencoding().lower().replace('-', '_')]
          if 'utf_8' not in default_encodings:
              default_encodings.append('utf_8')
          default_encodings = list(set(default_encodings))
          return json.loads(self._settings.value(
              'userDefinedEncodings', json.dumps(default_encodings)))