LocaleSettingsForm::buildForm

public LocaleSettingsForm::buildForm(array $form, FormStateInterface $form_state)

public function buildForm(array $form, FormStateInterface $form_state) {
  $config = $this->config('locale.settings');

  $form['update_interval_days'] = array(
    '#type' => 'radios',
    '#title' => $this->t('Check for updates'),
    '#default_value' => $config->get('translation.update_interval_days'),
    '#options' => array(
      '0' => $this->t('Never (manually)'),
      '7' => $this->t('Weekly'),
      '30' => $this->t('Monthly'),
    ),
    '#description' => $this->t('Select how frequently you want to check for new interface translations for your currently installed modules and themes. <a href=":url">Check updates now</a>.', array(':url' => $this->url('locale.check_translation'))),
  );

  if ($directory = $config->get('translation.path')) {
    $description = $this->t('Translation files are stored locally in the  %path directory. You can change this directory on the <a href=":url">File system</a> configuration page.', array('%path' => $directory, ':url' => $this->url('system.file_system_settings')));
  }
  else {
    $description = $this->t('Translation files will not be stored locally. Change the Interface translation directory on the <a href=":url">File system configuration</a> page.', array(':url' => $this->url('system.file_system_settings')));
  }
  $form['#translation_directory'] = $directory;
  $form['use_source'] = array(
    '#type' => 'radios',
    '#title' => $this->t('Translation source'),
    '#default_value' => $config->get('translation.use_source'),
    '#options' => array(
      LOCALE_TRANSLATION_USE_SOURCE_REMOTE_AND_LOCAL => $this->t('Drupal translation server and local files'),
      LOCALE_TRANSLATION_USE_SOURCE_LOCAL => $this->t('Local files only'),
    ),
    '#description' => $this->t('The source of translation files for automatic interface translation.') . ' ' . $description,
  );

  if ($config->get('translation.overwrite_not_customized') == FALSE) {
    $default = LOCALE_TRANSLATION_OVERWRITE_NONE;
  }
  elseif ($config->get('translation.overwrite_customized') == TRUE) {
    $default = LOCALE_TRANSLATION_OVERWRITE_ALL;
  }
  else {
    $default = LOCALE_TRANSLATION_OVERWRITE_NON_CUSTOMIZED;
  }
  $form['overwrite'] = array(
    '#type' => 'radios',
    '#title' => $this->t('Import behavior'),
    '#default_value' => $default,
    '#options' => array(
      LOCALE_TRANSLATION_OVERWRITE_NONE => $this->t("Don't overwrite existing translations."),
      LOCALE_TRANSLATION_OVERWRITE_NON_CUSTOMIZED => $this->t('Only overwrite imported translations, customized translations are kept.'),
      LOCALE_TRANSLATION_OVERWRITE_ALL => $this->t('Overwrite existing translations.'),
    ),
    '#description' => $this->t('How to treat existing translations when automatically updating the interface translations.'),
  );

  return parent::buildForm($form, $form_state);
}