Altering existing route for translation overview page ie: entity.node.content_translation_overview I have followed this documentation page :  https://www.drupal.org/docs/drupal-apis/routing-system/altering-existing-routes-and-adding-new-routes-based-on-dynamic-ones in attempt to alter access of translation overview page ie: www.example.com/node/1/translations
&lt;?php

namespace Drupal\link_enhancements\Routing;

use Drupal\Core\Routing\RouteSubscriberBase;
use Symfony\Component\Routing\Route;
use Symfony\Component\Routing\RouteCollection;

/**
 * Listens to the dynamic route events.
 */
class RouteSubscriber extends RouteSubscriberBase {

  /**
   * {@inheritdoc}
   */
  public function alterRoutes(RouteCollection $collection) {

    $route_name = &quot;entity.node.content_translation_overview&quot;;
    var_dump($collection-&gt;get($route_name)); exit;
    if ($route = $collection-&gt;get($route_name)) {
      $requirements = $route-&gt;getRequirements();
      unset($requirements['_permission']);
      // if both role then only we will allow ...code will go here.....
      $route-&gt;setRequirement('_access', 'FALSE');
    }

  }

}


services:
  link_enhancements.route_subscriber:
    class: Drupal\link_enhancements\Routing\RouteSubscriber
    tags:
      - { name: event_subscriber }

But below route output is null and similar code works for other routes but requirement to alter translation overview route which returns null.
$route_name = &quot;entity.node.content_translation_overview&quot;;
    var_dump($collection-&gt;get($route_name)); exit;

core/modules/content_translation/src/Routing/ContentTranslationRouteSubscriber.php
route is added in core module by below code and I have searched and tried but not sure how can we alter such routes, please suggest.
if ($entity_type-&gt;hasLinkTemplate('drupal:content-translation-overview')) {
        $route = new Route(
          $entity_type-&gt;getLinkTemplate('drupal:content-translation-overview'),
          [
            '_controller' =&gt; '\Drupal\content_translation\Controller\ContentTranslationController::overview',
            'entity_type_id' =&gt; $entity_type_id,
          ],
          [
            '_entity_access' =&gt; $entity_type_id . '.view',
            '_access_content_translation_overview' =&gt; $entity_type_id,
          ],
          [
            'parameters' =&gt; [
              $entity_type_id =&gt; [
                'type' =&gt; 'entity:' . $entity_type_id,
                'load_latest_revision' =&gt; $load_latest_revision,
              ],
            ],
            '_admin_route' =&gt; $is_admin,
          ]
        );
        $route_name = &quot;entity.$entity_type_id.content_translation_overview&quot;;
        $collection-&gt;add($route_name, $route);
      }
It was not working because in content_transaltion module priority was set to -210 so make need to change priority of custom module to -220 and it started working.
public static function getSubscribedEvents() {
    $events = parent::getSubscribedEvents();
    $events[RoutingEvents::ALTER] = ['onAlterRoutes', -220];
    return $events;
  }