code: def on_output_path_textChanged(self):
          
          output_path = self.output_path.text()
          output_not_xml_msg = tr('output file is not .tif')
          if output_path and not output_path.endswith('.tif'):
              self.warning_text.add(output_not_xml_msg)
          elif output_path and output_not_xml_msg in self.warning_text:
              self.warning_text.remove(output_not_xml_msg)
          self.update_warning()
docs: Action when output file name is changed.