LocaleSettingsForm::submitForm

public LocaleSettingsForm::submitForm(array &$form, FormStateInterface $form_state)

public function submitForm(array &$form, FormStateInterface $form_state) {
  $values = $form_state->getValues();

  $config = $this->config('locale.settings');
  $config->set('translation.update_interval_days', $values['update_interval_days'])->save();
  $config->set('translation.use_source', $values['use_source'])->save();

  switch ($values['overwrite']) {
    case LOCALE_TRANSLATION_OVERWRITE_ALL:
      $config
      ->set('translation.overwrite_customized', TRUE)
        ->set('translation.overwrite_not_customized', TRUE)
        ->save();
      break;

    case LOCALE_TRANSLATION_OVERWRITE_NON_CUSTOMIZED:
      $config
      ->set('translation.overwrite_customized', FALSE)
        ->set('translation.overwrite_not_customized', TRUE)
        ->save();
      break;

    case LOCALE_TRANSLATION_OVERWRITE_NONE:
      $config
      ->set('translation.overwrite_customized', FALSE)
        ->set('translation.overwrite_not_customized', FALSE)
        ->save();
      break;
  }

  // Invalidate the cached translation status when the configuration setting
  // of 'use_source' changes.
  if ($form['use_source']['#default_value'] != $form_state->getValue('use_source')) {
    locale_translation_clear_status();
  }

  parent::submitForm($form, $form_state);
}