docs: def _on_process_stderr_ready(self):
          """ Logs process output (stderr) """
          try:
              o = self.readAllStandardError()
          except (TypeError, RuntimeError):
              # widget already deleted
              return
          try:
              output = bytes(o).decode(self._encoding)
          except TypeError:
              output = bytes(o.data()).decode(self._encoding)
          for line in output.splitlines():
              self._srv_logger.error(line)