Issue #3029819 by tim.plunkett, bnjmnm, tedbow, xjm: Do not allow Page Title block to be placed in Layout Builder until it works properly

core/modules/layout_builder/layout_builder.module

@@ -174,6 +174,14 @@ function layout_builder_cron() {
   }
 }
 
+/**
+ * Implements hook_plugin_filter_TYPE__CONSUMER_alter().
+ */
+function layout_builder_plugin_filter_block__layout_builder_alter(array &$definitions, array $extra) {
+  // @todo Restore the page title block in https://www.drupal.org/node/2938129.
+  unset($definitions['page_title_block']);
+}
+
 /**
  * Implements hook_plugin_filter_TYPE_alter().
  */

core/modules/layout_builder/tests/src/Functional/LayoutBuilderTest.php

@@ -514,6 +514,7 @@ class LayoutBuilderTest extends BrowserTestBase {
     // Verify that blocks explicitly removed are not present.
     $assert_session->linkNotExists('Help');
     $assert_session->linkNotExists('Sticky at top of lists');
+    $assert_session->linkNotExists('Page title');
 
     // Verify that Changed block is not present on first section.
     $assert_session->linkNotExists('Changed');