system_theme_suggestions_maintenance_page

system_theme_suggestions_maintenance_page(array $variables)

function system_theme_suggestions_maintenance_page(array $variables) {
  $suggestions = array();

  // Dead databases will show error messages so supplying this template will
  // allow themers to override the page and the content completely.
  $offline = defined('MAINTENANCE_MODE');
  try {
    \Drupal::service('path.matcher')->isFrontPage();
  }
  catch (Exception $e) {
    // The database is not yet available.
    $offline = TRUE;
  }
  if ($offline) {
    $suggestions[] = 'maintenance_page__offline';
  }

  return $suggestions;
}