dpi
--- a/core/lib/Drupal/Core/Render/MainContent/HtmlRenderer.php
+++ b/core/lib/Drupal/Core/Render/MainContent/HtmlRenderer.php
  protected function prepare(array $main_content, Request $request, RouteMatchInterface $route_match) {
    // Determine the title: use the title provided by the main content if any,
    // otherwise get it from the routing information.
-    $get_title = function (array $main_content) use ($request, $route_match) {
+    $get_title = function (array $main_content) use ($request, $route_match): array|string|\Stringable|null {
      return $main_content['#title'] ?? $this->titleResolver->getTitle($request, $route_match->getRouteObject());
--- a/core/lib/Drupal/Core/Render/MainContent/HtmlRenderer.php
+++ b/core/lib/Drupal/Core/Render/MainContent/HtmlRenderer.php
      }
      $page_display
        ->setMainContent($main_content)
-        ->setTitle($title)
        ->addCacheableDependency($event);
+
+      $title = $get_title($main_content);
+      if ($title !== NULL) {