CacheRouterRebuildSubscriber.php

<?php

namespace Drupal\Core\EventSubscriber;

use Drupal\Core\Cache\Cache;
use Drupal\Core\Routing\RoutingEvents;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;

/**
 * Clear cache tags when the router is rebuilt.
 */
class CacheRouterRebuildSubscriber implements EventSubscriberInterface {
    
    /**
     * {@inheritdoc}
     */
    public function onRouterFinished() {
        // Requested URLs that formerly gave a 403/404 may now be valid.
        // Also invalidate all cached routing as well as every HTTP response.
        Cache::invalidateTags([
            '4xx-response',
            'route_match',
            'http_response',
        ]);
    }
    
    /**
     * {@inheritdoc}
     */
    public static function getSubscribedEvents() {
        $events = [];
        // Act only when the router rebuild is finished.
        $events[RoutingEvents::FINISHED][] = [
            'onRouterFinished',
            200,
        ];
        return $events;
    }

}