diff --git a/page_manager.post_update.php b/page_manager.post_update.php
index 320948c..fdf8e37 100644
--- a/page_manager.post_update.php
+++ b/page_manager.post_update.php
@@ -41,3 +41,10 @@ function page_manager_post_update_replace_current_user_context(&$sandbox = NULL)
       $pageVariant->save();
     });
 }
+
+/**
+ * Update container for page_manager.page_access_check arguments.
+ */
+function page_manager_post_update_page_access_check_service_refactor() {
+  // Intentionally empty to trigger a service container rebuild.
+}
diff --git a/page_manager.services.yml b/page_manager.services.yml
index f37751e..95f67ca 100644
--- a/page_manager.services.yml
+++ b/page_manager.services.yml
@@ -38,5 +38,7 @@ services:
     arguments: ['@current_route_match']
   page_manager.page_access_check:
     class: Drupal\page_manager\Entity\PageAccessCheck
+    arguments:
+      - '@entity_type.manager'
     tags:
       - { name: access_check, applies_to: _page_access }
diff --git a/src/Entity/PageAccessCheck.php b/src/Entity/PageAccessCheck.php
index ac3c93c..ebdf680 100644
--- a/src/Entity/PageAccessCheck.php
+++ b/src/Entity/PageAccessCheck.php
@@ -2,7 +2,10 @@
 
 namespace Drupal\page_manager\Entity;
 
-use Drupal\Core\Entity\EntityAccessCheck;
+use Drupal\Core\Access\AccessResult;
+use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Entity\EntityTypeManagerInterface;
+use Drupal\Core\Routing\Access\AccessInterface;
 use Drupal\Core\Routing\RouteMatchInterface;
 use Drupal\Core\Session\AccountInterface;
 use Symfony\Component\Routing\Route;
@@ -10,23 +13,65 @@ use Symfony\Component\Routing\Route;
 /**
  * Mimics the generic entity access but with a custom key to prevent collisions.
  */
-class PageAccessCheck extends EntityAccessCheck {
+class PageAccessCheck implements AccessInterface {
 
   /**
-   * {@inheritdoc}
+   * The entity type manager.
+   *
+   * @var \Drupal\Core\Entity\EntityTypeManagerInterface
    */
-  public function access(Route $route, RouteMatchInterface $route_match, AccountInterface $account) {
-    // Backup the original requirements.
-    $original_requirements = $route->getRequirements();
+  protected EntityTypeManagerInterface $entityTypeManager;
+
+  /**
+   * Creates a new PageAccessCheck.
+   *
+   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entityTypeManager
+   *   The entity type manager.
+   */
+  public function __construct(EntityTypeManagerInterface $entityTypeManager) {
+    $this->entityTypeManager = $entityTypeManager;
+  }
 
-    // Replace it with our entity access value and run the parent access check.
-    $route->setRequirement('_entity_access', $route->getRequirement('_page_access'));
-    $access = parent::access($route, $route_match, $account);
+  /**
+   * Checks access to the page operation on the given route.
+   *
+   * We can not use _entity_access as route match can not see params that
+   * start with '_'.
+   *
+   * @param \Symfony\Component\Routing\Route $route
+   *   The route to check against.
+   * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
+   *   The parametrized route.
+   * @param \Drupal\Core\Session\AccountInterface $account
+   *   The currently logged in account.
+   *
+   * @see https://www.drupal.org/project/drupal/issues/3277784
+   * @see https://www.drupal.org/project/page_manager/issues/3362561
+   *
+   * @return \Drupal\Core\Access\AccessResultInterface
+   *   The access result.
+   */
+  public function access(Route $route, RouteMatchInterface $route_match, AccountInterface $account) {
+    // Try to load the page manager page from the route defaults.
+    $pageId = $route->getDefault('_page_manager_page');
+    if (!empty($pageId)) {
+      try {
+        $page = $this->entityTypeManager->getStorage('page')->load($pageId);
+      } catch (\Exception $e) {
+        // Could not load the entity, we fall back to the default behaviour.
+      }
+    }
 
-    // Restore the original requirements.
-    $route->setRequirements($original_requirements);
+    // If we could load a page, perform the 'view' access check on it.
+    // We always check the 'view' access, because that is the only operation
+    // for which we add this access check.
+    if (isset($page) && $page instanceof EntityInterface) {
+      return $page->access('view', $account, TRUE);
+    }
 
-    return $access;
+    // If no page could be found or loaded, we have no opinion, so other
+    // access checks should decide if access should be allowed or not.
+    return AccessResult::neutral();
   }
 
 }
diff --git a/src/EventSubscriber/RouteNameResponseSubscriber.php b/src/EventSubscriber/RouteNameResponseSubscriber.php
index ef695e1..b5f901b 100644
--- a/src/EventSubscriber/RouteNameResponseSubscriber.php
+++ b/src/EventSubscriber/RouteNameResponseSubscriber.php
@@ -43,7 +43,7 @@ class RouteNameResponseSubscriber implements EventSubscriberInterface {
       // If the route specifies a 'base route name', use that. Otherwise fall
       // back to the route name. The 'base route name' is specified in
       // \Drupal\page_manager\Routing\PageManagerRoutes.
-      $route_name = $this->routeMatch->getParameter('base_route_name') ?: $this->routeMatch->getRouteName();
+      $route_name = $this->routeMatch->getParameter('_base_route_name') ?: $this->routeMatch->getRouteName();
       $cacheability_metadata->addCacheTags(['page_manager_route_name:' . $route_name]);
     }
   }
diff --git a/src/EventSubscriber/RouteParamContext.php b/src/EventSubscriber/RouteParamContext.php
index 9a3a349..4c0895a 100644
--- a/src/EventSubscriber/RouteParamContext.php
+++ b/src/EventSubscriber/RouteParamContext.php
@@ -61,7 +61,7 @@ class RouteParamContext implements EventSubscriberInterface {
     if ($route && $route_contexts = $route->getOption('parameters')) {
       foreach ($route_contexts as $route_context_name => $route_context) {
         // Skip this parameter.
-        if ($route_context_name == 'page_manager_page_variant' || $route_context_name == 'page_manager_page') {
+        if ($route_context_name == '_page_manager_page_variant' || $route_context_name == '_page_manager_page') {
           continue;
         }
 
diff --git a/src/Routing/PageManagerRoutes.php b/src/Routing/PageManagerRoutes.php
index d821b7d..017a3ae 100644
--- a/src/Routing/PageManagerRoutes.php
+++ b/src/Routing/PageManagerRoutes.php
@@ -66,7 +66,7 @@ class PageManagerRoutes extends RouteSubscriberBase {
         $collection_route = $collection->get($overridden_route_name);
 
         // Add the name of the overridden route for use during filtering.
-        $defaults['overridden_route_name'] = $overridden_route_name;
+        $defaults['_overridden_route_name'] = $overridden_route_name;
         $path = $collection_route->getPath();
         $parameters = $collection_route->getOption('parameters') ?: [];
         $requirements = $collection_route->getRequirements();
@@ -89,21 +89,21 @@ class PageManagerRoutes extends RouteSubscriberBase {
       // When adding multiple variants, the variant ID is added to the route
       // name. In order to convey the base route name for this set of variants,
       // add it as a parameter.
-      $defaults['base_route_name'] = $base_route_name;
+      $defaults['_base_route_name'] = $base_route_name;
 
-      $defaults['_entity_view'] = 'page_manager_page_variant';
+      $defaults['_entity_view'] = '_page_manager_page_variant';
       $defaults['_title'] = $entity->label();
-      $defaults['page_manager_page'] = $entity->id();
-      $parameters['page_manager_page_variant']['type'] = 'entity:page_variant';
-      $parameters['page_manager_page']['type'] = 'entity:page';
-      $requirements['_page_access'] = 'page_manager_page.view';
+      $defaults['_page_manager_page'] = $entity->id();
+      $parameters['_page_manager_page_variant']['type'] = 'entity:page_variant';
+      $parameters['_page_manager_page']['type'] = 'entity:page';
+      $requirements['_page_access'] = '_page_manager_page.view';
       foreach ($entity->getVariants() as $variant_id => $variant) {
         // Construct and add a new route.
         $route = new Route(
           $path,
           $defaults + [
-            'page_manager_page_variant' => $variant_id,
-            'page_manager_page_variant_weight' => $variant->getWeight(),
+            '_page_manager_page_variant' => $variant_id,
+            '_page_manager_page_variant_weight' => $variant->getWeight(),
           ],
           $requirements,
           [
diff --git a/src/Routing/VariantRouteFilter.php b/src/Routing/VariantRouteFilter.php
index a666583..a770f49 100644
--- a/src/Routing/VariantRouteFilter.php
+++ b/src/Routing/VariantRouteFilter.php
@@ -71,7 +71,7 @@ class VariantRouteFilter implements FilterInterface {
     $routes = $collection->all();
     // Only continue if at least one route has a page manager variant.
     if (!array_filter($routes, function (Route $route) {
-      return $route->hasDefault('page_manager_page_variant');
+      return $route->hasDefault('_page_manager_page_variant');
     })) {
       return $collection;
     }
@@ -81,7 +81,7 @@ class VariantRouteFilter implements FilterInterface {
 
     $variant_route_name = $this->getVariantRouteName($routes, $request);
     foreach ($routes as $name => $route) {
-      if (!$route->hasDefault('page_manager_page_variant')) {
+      if (!$route->hasDefault('_page_manager_page_variant')) {
         continue;
       }
 
@@ -91,7 +91,7 @@ class VariantRouteFilter implements FilterInterface {
       }
       // If the selected route is overriding another route, remove the
       // overridden route.
-      elseif ($overridden_route_name = $route->getDefault('overridden_route_name')) {
+      elseif ($overridden_route_name = $route->getDefault('_overridden_route_name')) {
         unset($routes[$overridden_route_name]);
       }
     }
@@ -100,7 +100,7 @@ class VariantRouteFilter implements FilterInterface {
     // the overridden_route_name if available.
     $result_collection = new RouteCollection();
     foreach ($routes as $name => $route) {
-      $overridden_route_name = $route->getDefault('overridden_route_name') ?: $name;
+      $overridden_route_name = $route->getDefault('_overridden_route_name') ?: $name;
       $result_collection->add($overridden_route_name, $route);
     }
     return $result_collection;
@@ -121,13 +121,13 @@ class VariantRouteFilter implements FilterInterface {
     // Store the unaltered request attributes.
     $original_attributes = $request->attributes->all();
     foreach ($routes as $name => $route) {
-      if (!$page_variant_id = $route->getDefault('page_manager_page_variant')) {
+      if (!$page_variant_id = $route->getDefault('_page_manager_page_variant')) {
         continue;
       }
 
       if ($attributes = $this->getRequestAttributes($route, $name, $request)) {
         // Use the overridden route name if available.
-        $attributes[RouteObjectInterface::ROUTE_NAME] = $route->getDefault('overridden_route_name') ?: $name;
+        $attributes[RouteObjectInterface::ROUTE_NAME] = $route->getDefault('_overridden_route_name') ?: $name;
         // Add the enhanced attributes to the request.
         $request->attributes->add($attributes);
         $this->requestStack->push($request);
@@ -160,7 +160,7 @@ class VariantRouteFilter implements FilterInterface {
   protected function sortRoutes(array $unsorted_routes) {
     // Create a mapping of route names to their weights.
     $weights_by_key = array_map(function (Route $route) {
-      return $route->getDefault('page_manager_page_variant_weight') ?: 0;
+      return $route->getDefault('_page_manager_page_variant_weight') ?: 0;
     }, $unsorted_routes);
 
     // Create an array holding the route names to be sorted.
diff --git a/tests/src/Unit/PageManagerRoutesTest.php b/tests/src/Unit/PageManagerRoutesTest.php
index 20e76f9..8917213 100644
--- a/tests/src/Unit/PageManagerRoutesTest.php
+++ b/tests/src/Unit/PageManagerRoutesTest.php
@@ -126,23 +126,23 @@ class PageManagerRoutesTest extends UnitTestCase {
     $this->assertSame(['page_manager.page_view_page1_variant1'], array_keys($collection->all()));
     $route = $collection->get('page_manager.page_view_page1_variant1');
     $expected_defaults = [
-      '_entity_view' => 'page_manager_page_variant',
+      '_entity_view' => '_page_manager_page_variant',
       '_title' => 'Page label',
-      'page_manager_page_variant' => 'variant1',
-      'page_manager_page' => 'page1',
-      'page_manager_page_variant_weight' => 0,
-      'base_route_name' => 'page_manager.page_view_page1',
+      '_page_manager_page_variant' => 'variant1',
+      '_page_manager_page' => 'page1',
+      '_page_manager_page_variant_weight' => 0,
+      '_base_route_name' => 'page_manager.page_view_page1',
     ];
     $expected_requirements = [
-      '_page_access' => 'page_manager_page.view',
+      '_page_access' => '_page_manager_page.view',
     ];
     $expected_options = [
       'compiler_class' => 'Symfony\Component\Routing\RouteCompiler',
       'parameters' => [
-        'page_manager_page_variant' => [
+        '_page_manager_page_variant' => [
           'type' => 'entity:page_variant',
         ],
-        'page_manager_page' => [
+        '_page_manager_page' => [
           'type' => 'entity:page',
         ],
       ],
@@ -204,23 +204,23 @@ class PageManagerRoutesTest extends UnitTestCase {
 
     $route = $collection->get('page_manager.page_view_page1_variant1');
     $expected_defaults = [
-      '_entity_view' => 'page_manager_page_variant',
+      '_entity_view' => '_page_manager_page_variant',
       '_title' => NULL,
-      'page_manager_page_variant' => 'variant1',
-      'page_manager_page' => 'page1',
-      'page_manager_page_variant_weight' => 0,
-      'overridden_route_name' => 'test_route',
-      'base_route_name' => 'test_route',
+      '_page_manager_page_variant' => 'variant1',
+      '_page_manager_page' => 'page1',
+      '_page_manager_page_variant_weight' => 0,
+      '_overridden_route_name' => 'test_route',
+      '_base_route_name' => 'test_route',
     ];
-    $expected_requirements = $requirements + ['_page_access' => 'page_manager_page.view'];
+    $expected_requirements = $requirements + ['_page_access' => '_page_manager_page.view'];
     $expected_options = [
       'compiler_class' => 'Symfony\Component\Routing\RouteCompiler',
       'parameters' => [
         'foo' => ['type' => 'bar'],
-        'page_manager_page_variant' => [
+        '_page_manager_page_variant' => [
           'type' => 'entity:page_variant',
         ],
-        'page_manager_page' => [
+        '_page_manager_page' => [
           'type' => 'entity:page',
         ],
       ],
@@ -293,25 +293,25 @@ class PageManagerRoutesTest extends UnitTestCase {
       'page_manager.page_view_page1_variant1' => [
         'path' => '/test_route1',
         'defaults' => [
-          '_entity_view' => 'page_manager_page_variant',
+          '_entity_view' => '_page_manager_page_variant',
           '_title' => 'Page 1',
-          'page_manager_page_variant' => 'variant1',
-          'page_manager_page' => 'page1',
-          'page_manager_page_variant_weight' => 0,
-          'overridden_route_name' => 'test_route',
-          'base_route_name' => 'test_route',
+          '_page_manager_page_variant' => 'variant1',
+          '_page_manager_page' => 'page1',
+          '_page_manager_page_variant_weight' => 0,
+          '_overridden_route_name' => 'test_route',
+          '_base_route_name' => 'test_route',
         ],
         'requirements' => [
           '_access' => 'TRUE',
-          '_page_access' => 'page_manager_page.view',
+          '_page_access' => '_page_manager_page.view',
         ],
         'options' => [
           'compiler_class' => 'Symfony\Component\Routing\RouteCompiler',
           'parameters' => [
-            'page_manager_page_variant' => [
+            '_page_manager_page_variant' => [
               'type' => 'entity:page_variant',
             ],
-            'page_manager_page' => [
+            '_page_manager_page' => [
               'type' => 'entity:page',
             ],
           ],
@@ -321,23 +321,23 @@ class PageManagerRoutesTest extends UnitTestCase {
       'page_manager.page_view_page2_variant2' => [
         'path' => '/test_route2',
         'defaults' => [
-          '_entity_view' => 'page_manager_page_variant',
+          '_entity_view' => '_page_manager_page_variant',
           '_title' => 'Page 2',
-          'page_manager_page_variant' => 'variant2',
-          'page_manager_page' => 'page2',
-          'page_manager_page_variant_weight' => 0,
-          'base_route_name' => 'page_manager.page_view_page2',
+          '_page_manager_page_variant' => 'variant2',
+          '_page_manager_page' => 'page2',
+          '_page_manager_page_variant_weight' => 0,
+          '_base_route_name' => 'page_manager.page_view_page2',
         ],
         'requirements' => [
-          '_page_access' => 'page_manager_page.view',
+          '_page_access' => '_page_manager_page.view',
         ],
         'options' => [
           'compiler_class' => 'Symfony\Component\Routing\RouteCompiler',
           'parameters' => [
-            'page_manager_page_variant' => [
+            '_page_manager_page_variant' => [
               'type' => 'entity:page_variant',
             ],
-            'page_manager_page' => [
+            '_page_manager_page' => [
               'type' => 'entity:page',
             ],
           ],
@@ -382,15 +382,15 @@ class PageManagerRoutesTest extends UnitTestCase {
     $this->routeSubscriber->onAlterRoutes($route_event);
 
     $expected_defaults = [
-      '_entity_view' => 'page_manager_page_variant',
+      '_entity_view' => '_page_manager_page_variant',
       '_title' => NULL,
-      'page_manager_page_variant' => 'variant1',
-      'page_manager_page' => 'page1',
-      'page_manager_page_variant_weight' => 0,
-      'overridden_route_name' => $route_name,
-      'base_route_name' => 'test_route',
+      '_page_manager_page_variant' => 'variant1',
+      '_page_manager_page' => 'page1',
+      '_page_manager_page_variant_weight' => 0,
+      '_overridden_route_name' => $route_name,
+      '_base_route_name' => 'test_route',
     ];
-    $expected_requirements = $requirements + ['_page_access' => 'page_manager_page.view'];
+    $expected_requirements = $requirements + ['_page_access' => '_page_manager_page.view'];
     $expected_options = [
       'compiler_class' => 'Symfony\Component\Routing\RouteCompiler',
       'parameters' => [
@@ -398,10 +398,10 @@ class PageManagerRoutesTest extends UnitTestCase {
           'bar' => 'bar',
           'type' => 'integer',
         ],
-        'page_manager_page_variant' => [
+        '_page_manager_page_variant' => [
           'type' => 'entity:page_variant',
         ],
-        'page_manager_page' => [
+        '_page_manager_page' => [
           'type' => 'entity:page',
         ],
       ],
diff --git a/tests/src/Unit/RouteNameResponseSubscriberTest.php b/tests/src/Unit/RouteNameResponseSubscriberTest.php
index b46400b..71a2a6b 100644
--- a/tests/src/Unit/RouteNameResponseSubscriberTest.php
+++ b/tests/src/Unit/RouteNameResponseSubscriberTest.php
@@ -29,7 +29,7 @@ class RouteNameResponseSubscriberTest extends UnitTestCase {
 
     $route_name = 'the_route_name';
     $master_route_match = $this->prophesize(RouteMatchInterface::class);
-    $master_route_match->getParameter('base_route_name')->willReturn(NULL);
+    $master_route_match->getParameter('_base_route_name')->willReturn(NULL);
     $master_route_match->getRouteName()->willReturn($route_name);
     $current_route_match = $this->prophesize(StackedRouteMatchInterface::class);
     $current_route_match->getMasterRouteMatch()->willReturn($master_route_match->reveal());
@@ -67,7 +67,7 @@ class RouteNameResponseSubscriberTest extends UnitTestCase {
 
     $route_name = 'the_route_name';
     $master_route_match = $this->prophesize(RouteMatchInterface::class);
-    $master_route_match->getParameter('base_route_name')->willReturn($route_name);
+    $master_route_match->getParameter('_base_route_name')->willReturn($route_name);
     $master_route_match->getRouteName()->shouldNotBeCalled();
     $current_route_match = $this->prophesize(StackedRouteMatchInterface::class);
     $current_route_match->getMasterRouteMatch()->willReturn($master_route_match->reveal());
diff --git a/tests/src/Unit/VariantRouteFilterTest.php b/tests/src/Unit/VariantRouteFilterTest.php
index 5cdb9ec..85a96bf 100644
--- a/tests/src/Unit/VariantRouteFilterTest.php
+++ b/tests/src/Unit/VariantRouteFilterTest.php
@@ -106,7 +106,7 @@ class VariantRouteFilterTest extends UnitTestCase {
     $route_collection = new RouteCollection();
     $request = new Request();
 
-    $route = new Route('/path/with/{slug}', ['page_manager_page_variant' => 'a_variant']);
+    $route = new Route('/path/with/{slug}', ['_page_manager_page_variant' => 'a_variant']);
     $route_collection->add('a_route', $route);
 
     $page_variant = $this->prophesize(PageVariantInterface::class);
@@ -149,7 +149,7 @@ class VariantRouteFilterTest extends UnitTestCase {
     $route_collection = new RouteCollection();
     $request = new Request();
 
-    $route = new Route('/path/with/{slug}', ['page_manager_page_variant' => 'a_variant']);
+    $route = new Route('/path/with/{slug}', ['_page_manager_page_variant' => 'a_variant']);
     $route_collection->add('a_route', $route);
 
     $page_variant = $this->prophesize(PageVariantInterface::class);
@@ -173,7 +173,7 @@ class VariantRouteFilterTest extends UnitTestCase {
     $route_collection = new RouteCollection();
     $request = new Request();
 
-    $route = new Route('/path/with/{slug}', ['page_manager_page_variant' => 'a_variant']);
+    $route = new Route('/path/with/{slug}', ['_page_manager_page_variant' => 'a_variant']);
     $route_collection->add('a_route', $route);
 
     $page_variant = $this->prophesize(PageVariantInterface::class);
@@ -186,7 +186,7 @@ class VariantRouteFilterTest extends UnitTestCase {
     $expected = ['a_route' => $route];
     $this->assertSame($expected, $result->all());
     $expected_attributes = [
-      'page_manager_page_variant' => 'a_variant',
+      '_page_manager_page_variant' => 'a_variant',
       '_route_object' => $route,
       '_route' => 'a_route',
       '_page_manager_attributes_prepared' => TRUE,
@@ -202,8 +202,8 @@ class VariantRouteFilterTest extends UnitTestCase {
     $route_collection = new RouteCollection();
     $request = new Request();
 
-    $route1 = new Route('/path/with/{slug}', ['page_manager_page_variant' => 'variant_1', 'page_manager_page_variant_weight' => 0]);
-    $route2 = new Route('/path/with/{slug}', ['page_manager_page_variant' => 'variant_2', 'page_manager_page_variant_weight' => 2]);
+    $route1 = new Route('/path/with/{slug}', ['_page_manager_page_variant' => 'variant_1', '_page_manager_page_variant_weight' => 0]);
+    $route2 = new Route('/path/with/{slug}', ['_page_manager_page_variant' => 'variant_2', '_page_manager_page_variant_weight' => 2]);
     // Add route2 first to ensure that the routes get sorted by weight.
     $route_collection->add('route_2', $route2);
     $route_collection->add('route_1', $route1);
@@ -219,8 +219,8 @@ class VariantRouteFilterTest extends UnitTestCase {
     $expected = ['route_1' => $route1];
     $this->assertSame($expected, $result->all());
     $expected_attributes = [
-      'page_manager_page_variant' => 'variant_1',
-      'page_manager_page_variant_weight' => 0,
+      '_page_manager_page_variant' => 'variant_1',
+      '_page_manager_page_variant_weight' => 0,
       '_route_object' => $route1,
       '_route' => 'route_1',
       '_page_manager_attributes_prepared' => TRUE,
@@ -236,11 +236,11 @@ class VariantRouteFilterTest extends UnitTestCase {
     $route_collection = new RouteCollection();
     $request = new Request();
 
-    $route1 = new Route('/path/with/{slug}', ['page_manager_page_variant' => 'variant_1', 'page_manager_page_variant_weight' => 1]);
+    $route1 = new Route('/path/with/{slug}', ['_page_manager_page_variant' => 'variant_1', '_page_manager_page_variant_weight' => 1]);
     $defaults = [
-      'page_manager_page_variant' => 'variant_2',
-      'page_manager_page_variant_weight' => 2,
-      'overridden_route_name' => 'overridden_route_name_for_selected_route',
+      '_page_manager_page_variant' => 'variant_2',
+      '_page_manager_page_variant_weight' => 2,
+      '_overridden_route_name' => 'overridden_route_name_for_selected_route',
     ];
     $route2 = new Route('/path/with/{slug}', $defaults);
     // Add route2 first to ensure that the routes get sorted by weight.
@@ -281,13 +281,13 @@ class VariantRouteFilterTest extends UnitTestCase {
 
     // The selected route specifies a different base route.
     $defaults = [
-      'page_manager_page_variant' => 'variant1',
-      'page_manager_page_variant_weight' => -2,
-      'overridden_route_name' => 'route_1',
+      '_page_manager_page_variant' => 'variant1',
+      '_page_manager_page_variant_weight' => -2,
+      '_overridden_route_name' => 'route_1',
     ];
     $route1 = new Route('/path/with/{slug}');
     $route2 = new Route('/path/with/{slug}', $defaults);
-    $route3 = new Route('/path/with/{slug}', ['page_manager_page_variant' => 'variant2', 'page_manager_page_variant_weight' => -1]);
+    $route3 = new Route('/path/with/{slug}', ['_page_manager_page_variant' => 'variant2', '_page_manager_page_variant_weight' => -1]);
     $route4 = new Route('/path/with/{slug}');
     // Add routes in different order to test sorting.
     $route_collection->add('route_3', $route3);
@@ -323,7 +323,7 @@ class VariantRouteFilterTest extends UnitTestCase {
     $route_collection = new RouteCollection();
     $request = new Request([], [], ['foo' => 'bar', 'slug' => 2]);
 
-    $route = new Route('/path/with/{slug}', ['page_manager_page_variant' => 'a_variant']);
+    $route = new Route('/path/with/{slug}', ['_page_manager_page_variant' => 'a_variant']);
     $route_collection->add('a_route', $route);
 
     $page_variant = $this->prophesize(PageVariantInterface::class);
@@ -337,7 +337,7 @@ class VariantRouteFilterTest extends UnitTestCase {
     $result_enhance_attributes = $expected_enhance_attributes = [
       'foo' => 'bar',
       'slug' => '1',
-      'page_manager_page_variant' => 'a_variant',
+      '_page_manager_page_variant' => 'a_variant',
       '_route_object' => $route,
       '_route' => 'a_route',
     ];
@@ -350,7 +350,7 @@ class VariantRouteFilterTest extends UnitTestCase {
     $expected_attributes = [
       'foo' => 'bar',
       'slug' => 'slug 1',
-      'page_manager_page_variant' => 'a_variant',
+      '_page_manager_page_variant' => 'a_variant',
       '_route_object' => $route,
       '_route' => 'a_route',
       '_page_manager_attributes_prepared' => TRUE,
@@ -368,7 +368,7 @@ class VariantRouteFilterTest extends UnitTestCase {
     $original_attributes = ['foo' => 'bar', 'slug' => 2];
     $request = new Request([], [], $original_attributes);
 
-    $route = new Route('/path/with/{slug}', ['page_manager_page_variant' => 'a_variant']);
+    $route = new Route('/path/with/{slug}', ['_page_manager_page_variant' => 'a_variant']);
     $route_collection->add('a_route', $route);
 
     $page_variant = $this->prophesize(PageVariantInterface::class);
@@ -382,7 +382,7 @@ class VariantRouteFilterTest extends UnitTestCase {
     $expected_enhance_attributes = [
       'foo' => 'bar',
       'slug' => '1',
-      'page_manager_page_variant' => 'a_variant',
+      '_page_manager_page_variant' => 'a_variant',
       '_route_object' => $route,
       '_route' => 'a_route',
     ];
@@ -402,8 +402,8 @@ class VariantRouteFilterTest extends UnitTestCase {
     $request = new Request();
 
     // Add routes in different order to also test order preserving.
-    $route1 = new Route('/path/with/{slug}', ['page_manager_page_variant' => 'variant1', 'page_manager_page_variant_weight' => -10, 'overridden_route_name' => 'preserved_route_name']);
-    $route2 = new Route('/path/with/{slug}', ['page_manager_page_variant' => 'variant2', 'page_manager_page_variant_weight' => -5]);
+    $route1 = new Route('/path/with/{slug}', ['_page_manager_page_variant' => 'variant1', '_page_manager_page_variant_weight' => -10, '_overridden_route_name' => 'preserved_route_name']);
+    $route2 = new Route('/path/with/{slug}', ['_page_manager_page_variant' => 'variant2', '_page_manager_page_variant_weight' => -5]);
     $route3 = new Route('/path/with/{slug}', []);
     $route4 = new Route('/path/with/{slug}', []);
     $route_collection->add('route_4', $route4);
