/**
 * Implements hook_views_preview_info_alter().
 */
function {{ machine_name }}_views_preview_info_alter(array &$rows, ViewExecutable $view) {
  // Adds information about the tables being queried by the view to the query
  // part of the info box.
  $rows['query'][] = [
    t('<strong>Table queue</strong>'),
    count($view->query->table_queue) . ': (' . implode(', ', array_keys($view->query->table_queue)) . ')',
  ];
}