Drupal 8: Add a class to the more link of a view.

/**

 * Implements template_preprocess_views_view()

 * @param array $vars

 */

function MYTHEME_preprocess_views_view(&$variables) {

  if ($variables['id'] == 'MY_VIEW_ID') {

    $variables['more']['#options']['attributes']['class'] = array(

      'button'

    );

  }

}