/**
 * Prepares variables for views-style-{{ plugin_id|u2h }}.html.twig template.
 */
function template_preprocess_views_style_{{ plugin_id }}(&$variables) {
  $handler = $variables['view']->style_plugin;

  // Fetch wrapper classes from handler options.
  if ($handler->options['wrapper_class']) {
    $wrapper_class = explode(' ', $handler->options['wrapper_class']);
    $variables['attributes']['class'] = array_map('\Drupal\Component\Utility\Html::cleanCssIdentifier', $wrapper_class);
  }

  template_preprocess_views_view_unformatted($variables);
}