code: def on_open_output_tool_clicked(self):
          
          output_path = self.output_path.text()
          if not output_path:
              output_path = os.path.expanduser('~')
          # noinspection PyCallByClass,PyTypeChecker
          filename, __ = QFileDialog.getSaveFileName(
              self, tr('Output file'), output_path, tr('Raster file (*.tif)'))
          if filename:
              self.output_path.setText(filename)
docs: Autoconnect slot activated when open output tool button is clicked.