code: protected function processData()
      {
          $close = GeneralUtility::_GP('closeDoc');
          $save = GeneralUtility::_GP('_savedok');
          $saveAndClose = GeneralUtility::_GP('_saveandclosedok');
  
          if ($save || $saveAndClose) {
              $table = static::virtualTable;
              $id = static::virtualRecordId;
              $field = 'rulesets';
  
              $inputData_tmp = GeneralUtility::_GP('data');
              $data = $inputData_tmp[$table][$id];
  
              if (count($inputData_tmp[$table]) > 1) {
                  foreach ($inputData_tmp[$table] as $key => $values) {
                      if ($key === $id) continue;
                      ArrayUtility::mergeRecursiveWithOverrule($data, $values);
                  }
              }
  
              $newConfig = $this->config;
              ArrayUtility::mergeRecursiveWithOverrule($newConfig, $data);
  
              // Action commands (sorting order and removals of FlexForm elements)
              $ffValue = &$data[$field];
              if ($ffValue) {
                  $actionCMDs = GeneralUtility::_GP('_ACTION_FLEX_FORMdata');
                  if (is_array($actionCMDs[$table][$id][$field]['data'])) {
                      $dataHandler = new CustomDataHandler();
                      $dataHandler->_ACTION_FLEX_FORMdata($ffValue['data'], $actionCMDs[$table][$id][$field]['data']);
                  }
                  // Renumber all FlexForm temporary ids
                  $this->persistFlexForm($ffValue['data']);
  
                  // Keep order of FlexForm elements
                  $newConfig[$field] = $ffValue;
              }
  
              // Persist configuration
              $localconfConfig = $newConfig;
              $localconfConfig['conversion_mapping'] = implode(',', GeneralUtility::trimExplode(LF, $localconfConfig['conversion_mapping'], true));
  
              if ($this->persistConfiguration($localconfConfig)) {
                  $this->config = $newConfig;
              }
          }
  
          if ($close || $saveAndClose) {
              $closeUrl = BackendUtility::getModuleUrl('tools_ExtensionmanagerExtensionmanager');
              \TYPO3\CMS\Core\Utility\HttpUtility::redirect($closeUrl);
          }
      }
docs: Processes submitted data and stores it to localconf.php.
  
  @return void