Issue #3104980 by danflanagan8, acbramley:...

 */

function layout_builder_system_breadcrumb_alter(Breadcrumb &$breadcrumb, RouteMatchInterface $route_match, array $context) {

  // Remove the extra 'Manage display' breadcrumb for Layout Builder defaults.

  if ($route_match->getRouteObject()->hasOption('_layout_builder') && $route_match->getParameter('section_storage_type') === 'defaults') {

  if ($route_match->getRouteObject() && $route_match->getRouteObject()->hasOption('_layout_builder') && $route_match->getParameter('section_storage_type') === 'defaults') {

    $links = array_filter($breadcrumb->getLinks(), function (Link $link) use ($route_match) {

      $entity_type_id = $route_match->getParameter('entity_type_id');

      if (!$link->getUrl()->isRouted()) {

<?php

namespace Drupal\Tests\layout_builder\Kernel;

use Drupal\Core\Breadcrumb\Breadcrumb;

use Drupal\Core\Routing\NullRouteMatch;

use Drupal\KernelTests\Core\Entity\EntityKernelTestBase;

/**

 * Tests layout_builder_system_breadcrumb_alter().

 *

 * @group layout_builder

 */

class LayoutBuilderBreadcrumbAlterTest extends EntityKernelTestBase {

  /**

   * {@inheritdoc}

   */

  protected static $modules = [

    'layout_builder',

    'layout_discovery',

  ];

  /**

   * Check that there are no errors when alter called with null route match.

   */

  public function testBreadcrumbAlterNullRouteMatch() {

    $breadcrumb = new Breadcrumb();

    $route_match = new NullRouteMatch();

    layout_builder_system_breadcrumb_alter($breadcrumb, $route_match, []);

  }

}