DecoupledMenusTestHooks.php

<?php

declare (strict_types=1);
namespace Drupal\decoupled_menus_test\Hook;

use Drupal\Core\Hook\Attribute\Hook;

/**
 * Hook implementations for decoupled_menus_test.
 */
class DecoupledMenusTestHooks {
  
  /**
   * Implements hook_menu_links_discovered_alter().
   */
  public function menuLinksDiscoveredAlter(&$links) : void {
    // Sets a custom link relation type on a menu item.
    // @see https://tools.ietf.org/id/draft-pot-authentication-link-01.html
    $links['user.page']['options']['attributes']['rel'] = 'authenticated-as';
  }

}