Michael Lander
--- a/src/EnvironmentIndicatorLazyBuilder.php 0 → 100644
+++ b/src/EnvironmentIndicatorLazyBuilder.php 0 → 100644
+<?php
+
+namespace Drupal\environment_indicator;
+
+use Drupal\Core\Cache\Cache;
+use Drupal\Core\Entity\EntityTypeManagerInterface;
+use Drupal\Core\Render\RendererInterface;
+use Drupal\Core\Security\TrustedCallbackInterface;
+use Drupal\Core\Session\AccountInterface;
+use Drupal\Core\Url;
+use Drupal\environment_indicator\Entity\EnvironmentIndicator;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
-use Drupal\Core\Cache\Cache;
-use Drupal\Core\Entity\EntityTypeManagerInterface;
-use Drupal\Core\Render\RendererInterface;
-use Drupal\Core\Security\TrustedCallbackInterface;
-use Drupal\Core\Session\AccountInterface;
-use Drupal\Core\Url;
-use Drupal\environment_indicator\Entity\EnvironmentIndicator;
-use Drupal\Core\StringTranslation\StringTranslationTrait;
+use Drupal\Core\Cache\Cache;
+use Drupal\Core\Entity\EntityTypeManagerInterface;
+use Drupal\Core\Render\RendererInterface;
+use Drupal\Core\Security\TrustedCallbackInterface;
+use Drupal\Core\Session\AccountInterface;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
+use Drupal\Core\Url;
+use Drupal\environment_indicator\Entity\EnvironmentIndicator;
--- a/css/environment_indicator-navigation.css 0 → 100644
+++ b/css/environment_indicator-navigation.css 0 → 100644
+/* Active environment button background and font colors. */
+.admin-toolbar .toolbar-button.toolbar-button--environment-indicator,
+.admin-toolbar .toolbar-button.toolbar-button--environment-indicator-label{
-.admin-toolbar .toolbar-button.toolbar-button--environment-indicator-label{
+.admin-toolbar .toolbar-button.toolbar-button--environment-indicator-label {
--- a/environment_indicator.module
+++ b/environment_indicator.module
  }
 }

+/**
+ * Implements hook_preprocess_navigation().
+ */
+function environment_indicator_preprocess_navigation (&$variables) {
-function environment_indicator_preprocess_navigation (&$variables) {
+function environment_indicator_preprocess_navigation(&$variables) {
--- a/environment_indicator.module
+++ b/environment_indicator.module
+    $custom_block_id = 'environment_indicator_navigation';
+    $definitions[$custom_block_id] = [
+      'class' => 'Drupal\environment_indicator\Plugin\Block\EnvironmentIndicatorNavigationBlock',
+      'provider' => 'environment_indicator_navigation',
+      'admin_label' => t('Environment Indicator'),
+      'category' => t('Navigation'),
+    ];
+  }
+}
+
+/**
+ * Implements hook_module_implements_alter().
+ */
+function environment_indicator_module_implements_alter(&$implementations, $hook) {
+  if ($hook === 'plugin_filter_block_alter' && isset($implementations['environment_indicator'])) {
+    $group = $implementations['environment_indicator'] ?? false;
-    $group = $implementations['environment_indicator'] ?? false;
+    $group = $implementations['environment_indicator'] ?? FALSE;
--- a/environment_indicator.module
+++ b/environment_indicator.module
    'environment_indicator' => [
      'render element' => 'element',
    ],
+    'navigation_menu__environment_indicator' => [
+      'variables' => [
+        'menu_name' => NULL,
+        'items' => [],
+        'attributes' => [],
+      ],
+      'base hook' => 'navigation_menu',
+    ]
-    ]
+    ],
--- a/src/Plugin/Block/EnvironmentIndicatorNavigationBlock.php 0 → 100644
+++ b/src/Plugin/Block/EnvironmentIndicatorNavigationBlock.php 0 → 100644
+
+use Drupal\Core\Access\AccessResult;
+use Drupal\Core\Access\AccessResultInterface;
+use Drupal\Core\Block\Attribute\Block;
+use Drupal\Core\Block\BlockBase;
+use Drupal\Core\Extension\ModuleHandlerInterface;
+use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
+use Drupal\Core\Session\AccountInterface;
+use Drupal\Core\StringTranslation\TranslatableMarkup;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Defines an environment indicator navigation block class.
+ *
+ * @internal
+ *
- *
--- a/src/EnvironmentIndicatorLazyBuilder.php 0 → 100644
+++ b/src/EnvironmentIndicatorLazyBuilder.php 0 → 100644
+
+  /**
+   * #lazy_builder callback; builds shortcut toolbar links.
+   *
+   * @param bool $show_configure_link
+   *   Boolean to indicate whether to include the configure link or not.
+   *
+   * @return array
+   *   A renderable array of shortcut links.
+   */
+  public function lazyLinks() {
+    $active_environment = \Drupal::config('environment_indicator.indicator');
+    $items = [
+      'environment_indicator' => [
+        'title' => $active_environment->get('name'),
+        'below' => $this->getBelowLinks()
-        'below' => $this->getBelowLinks()
+        'below' => $this->getBelowLinks(),
--- a/src/EnvironmentIndicatorLazyBuilder.php 0 → 100644
+++ b/src/EnvironmentIndicatorLazyBuilder.php 0 → 100644
+  public function lazyLinks() {
+    $active_environment = \Drupal::config('environment_indicator.indicator');
+    $items = [
+      'environment_indicator' => [
+        'title' => $active_environment->get('name'),
+        'below' => $this->getBelowLinks()
+      ],
+    ];
+
+    return [
+      '#theme' => 'navigation_menu__environment_indicator',
+      '#menu_name' => 'environment_indicator',
+      '#items' => $items,
+      '#cache' => Cache::mergeTags(['config:environment_indicator.settings'], _environment_indicator_switcher_cache_tags()),
+    ];
+  }
-  }
+  }
+
--- a/src/EnvironmentIndicatorLazyBuilder.php 0 → 100644
+++ b/src/EnvironmentIndicatorLazyBuilder.php 0 → 100644
+    return $links;
+  }
+
+  /**
+   * Check if the current user has access to the given environment.
+   *
+   * @param string $environment
+   *   The environment to check access for.
+   *
+   * @return bool
+   *   TRUE if the user has access, FALSE otherwise.
+   */
+  protected function hasAccessEnvironment($environment) {
+    return $this->currentUser->hasPermission('access environment indicator')
+      || $this->currentUser->hasPermission('access environment indicator ' . $environment);
+  }
-  }
+  }
+
--- a/environment_indicator.services.yml
+++ b/environment_indicator.services.yml
      - '@state'
      - '@settings'
      - '@entity_type.manager'
+  environment_indicator.lazy_builders:
+    class: Drupal\environment_indicator\EnvironmentIndicatorLazyBuilder
+    arguments: ['@renderer', '@entity_type.manager', '@current_user']
+  Drupal\environment_indicator\EnvironmentIndicatorLazyBuilder: '@environment_indicator.lazy_builders'
-  environment_indicator.lazy_builders:
-    class: Drupal\environment_indicator\EnvironmentIndicatorLazyBuilder
-    arguments: ['@renderer', '@entity_type.manager', '@current_user']
-  Drupal\environment_indicator\EnvironmentIndicatorLazyBuilder: '@environment_indicator.lazy_builders'
+  environment_indicator.lazy_builders:
+    class: Drupal\environment_indicator\EnvironmentIndicatorLazyBuilder
+    arguments:
+      - '@renderer'
+      - '@entity_type.manager'
+      - '@current_user'
+  Drupal\environment_indicator\EnvironmentIndicatorLazyBuilder: '@environment_indicator.lazy_builders'
--- a/environment_indicator.libraries.yml
+++ b/environment_indicator.libraries.yml
  dependencies:
    - core/jquery
    - core/once
+drupal.environment_indicator_navigation:
+  version: '3.0'
-  version: '3.0'
+  version: VERSION
--- a/templates/navigation-menu--environment-indicator.html.twig 0 → 100644
+++ b/templates/navigation-menu--environment-indicator.html.twig 0 → 100644
+{{ attach_library('environment_indicator/drupal.environment_indicator_navigation') }}
-{{ attach_library('environment_indicator/drupal.environment_indicator_navigation') }}
+{#
+/**
+ * @file
+ * Twig template for the environment indicator navigation in the admin toolbar.
+ *
+ * Attaches the 'environment_indicator/drupal.environment_indicator_navigation' library.
+ * Generates a structured navigation menu item within the Drupal admin toolbar.
+ *
+ * This template is rendered by the EnvironmentIndicatorNavigationBlock plugin.
+ *
+ * Available variables:
+ * - menu_name: The name of the menu being rendered.
+ * - title: The title of the menu block.
+ * - items: An array of menu items to be rendered.
+ *
+ * Logic:
+ * - Sets unique IDs for accessibility and identification purposes.
+ * - Checks if the menu item has children (`below`), and renders appropriate HTML structure.
+ * - Includes the '@navigation/toolbar-button.html.twig' template for rendering individual toolbar buttons.
+ *
+ * Attributes and Classes:
+ * - Assigns various attributes and classes to HTML elements for styling and functionality.
+ *
+ * @see \Drupal\environment_indicator\Plugin\Block\EnvironmentIndicatorNavigationBlock
+ */
+#}
+{{ attach_library('environment_indicator/drupal.environment_indicator_navigation') }}
--- a/src/EnvironmentIndicatorLazyBuilder.php 0 → 100644
+++ b/src/EnvironmentIndicatorLazyBuilder.php 0 → 100644
+   * @var \Drupal\Core\Render\RendererInterface
+   */
+  protected $renderer;
+
+  /**
+   * Constructs a new ShortcutLazyBuilders object.
+   *
+   * @param \Drupal\Core\Render\RendererInterface $renderer
+   *   The renderer service.
+   * @param \Drupal\Core\Entity\EntityTypeManagerInterface|null $entityTypeManager
+   *   The entity type manager.
+   * @param \Drupal\Core\Session\AccountInterface|null $currentUser
+   *   The current user.
+   */
+  public function __construct(RendererInterface $renderer, protected ?EntityTypeManagerInterface $entityTypeManager, protected ?AccountInterface $currentUser) {
+    $this->renderer = $renderer;
--- a/src/EnvironmentIndicatorLazyBuilder.php 0 → 100644
+++ b/src/EnvironmentIndicatorLazyBuilder.php 0 → 100644
+  public function __construct(RendererInterface $renderer, protected ?EntityTypeManagerInterface $entityTypeManager, protected ?AccountInterface $currentUser) {
+    $this->renderer = $renderer;
+    if (!isset($this->entityTypeManager)) {
+      @trigger_error('Calling ' . __METHOD__ . '() without the $entityTypeManager argument is deprecated in drupal:10.3.0 and will be required in drupal:11.0.0. See https://www.drupal.org/node/3427050', E_USER_DEPRECATED);
+      $this->entityTypeManager = \Drupal::entityTypeManager();
+    }
+    if (!isset($this->currentUser)) {
+      @trigger_error('Calling ' . __METHOD__ . '() without the $currentUser argument is deprecated in drupal:10.3.0 and will be required in drupal:11.0.0. See https://www.drupal.org/node/3427050', E_USER_DEPRECATED);
+      $this->currentUser = \Drupal::currentUser();
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function trustedCallbacks() {
--- a/src/EnvironmentIndicatorLazyBuilder.php 0 → 100644
+++ b/src/EnvironmentIndicatorLazyBuilder.php 0 → 100644
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function trustedCallbacks() {
+    return ['lazyLinks'];
+  }
+
+  /**
+   * #lazy_builder callback; builds shortcut toolbar links.
+   *
+   * @return array
+   *   A renderable array of shortcut links.
+   */
+  public function lazyLinks() {
+    $active_environment = \Drupal::config('environment_indicator.indicator');
--- a/src/EnvironmentIndicatorLazyBuilder.php 0 → 100644
+++ b/src/EnvironmentIndicatorLazyBuilder.php 0 → 100644
+    return [
+      '#theme' => 'navigation_menu__environment_indicator',
+      '#menu_name' => 'environment_indicator',
+      '#items' => $items,
+      '#cache' => Cache::mergeTags(['config:environment_indicator.settings'], _environment_indicator_switcher_cache_tags()),
+    ];
+  }
+
+  /**
+   * Get all the links for the switcher.
+   *
+   * @return array
+   *   Array of links for each configured environment.
+   */
+  protected function getBelowLinks(): array {
+    if (!$environment_entities = EnvironmentIndicator::loadMultiple()) {
-    if (!$environment_entities = EnvironmentIndicator::loadMultiple()) {
+    if (!$environment_entities = $this->entityTypeManager->getStorage('environment_indicator')->loadMultiple()) {
--- a/src/EnvironmentIndicatorLazyBuilder.php 0 → 100644
+++ b/src/EnvironmentIndicatorLazyBuilder.php 0 → 100644
+   */
+  public function lazyLinks() {
+    $active_environment = \Drupal::config('environment_indicator.indicator');
+    $items = [
+      'environment_indicator' => [
+        'title' => $active_environment->get('name'),
+        'below' => $this->getBelowLinks(),
+        'class' => $active_environment->get('name'),
+      ],
+    ];
+
+    return [
+      '#theme' => 'navigation_menu__environment_indicator',
+      '#menu_name' => 'environment_indicator',
+      '#items' => $items,
+      '#cache' => Cache::mergeTags(['config:environment_indicator.settings'], _environment_indicator_switcher_cache_tags()),
-      '#cache' => Cache::mergeTags(['config:environment_indicator.settings'], _environment_indicator_switcher_cache_tags()),
+      '#cache' => [
+        'tags' => Cache::mergeTags(['config:environment_indicator.settings'], _environment_indicator_switcher_cache_tags()),
+        'contexts' => ['route', 'user.permissions'],
+      ]
--- a/src/Plugin/Block/EnvironmentIndicatorNavigationBlock.php 0 → 100644
+++ b/src/Plugin/Block/EnvironmentIndicatorNavigationBlock.php 0 → 100644
+   * {@inheritdoc}
+   */
+  protected function blockAccess(AccountInterface $account): AccessResultInterface {
+    return AccessResult::allowedIfHasPermission($account, 'access environment indicator');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function build(): array {
+
+    return [
+      '#lazy_builder' => ['environment_indicator.lazy_builders:lazyLinks', []],
+      '#create_placeholder' => TRUE,
+      '#cache' => [
+        'contexts' => ['user'],
-        'contexts' => ['user'],
+        'contexts' => ['user.permissions'],
--- a/src/ToolbarHandler.php
+++ b/src/ToolbarHandler.php
        }
      }
    }
+    elseif ($integration === 'navigation') {
+      if ($this->moduleHandler->moduleExists('navigation')) {
+        $cacheability = new CacheableMetadata();
--- a/environment_indicator.services.yml
+++ b/environment_indicator.services.yml
      - '@state'
      - '@settings'
      - '@entity_type.manager'
+      - '@plugin.manager.layout_builder.section_storage'
--- a/src/ToolbarHandler.php
+++ b/src/ToolbarHandler.php
   *   TRUE if integration is enabled. FALSE otherwise.
   */
  public function externalIntegration($integration): bool {
+    if ($integration == 'toolbar') {
+      return $this->hasExternalToolbarIntegration();
+    }
+    elseif ($integration == 'navigation') {
+      return $this->hasExternalNavigationIntegration();
+    }
+    return FALSE;
+
    if ($integration == 'toolbar') {
--- a/src/ToolbarHandler.php
+++ b/src/ToolbarHandler.php
    return $links;
  }

-}
+  /**
+   * Get the section storage manager from layout builder as soft dependency.
+   *
+   * @throws \RuntimeException
+   *   When layout_builder module is not enabled.
+   *
+   * @return \Drupal\layout_builder\SectionStorage\SectionStorageManagerInterface
+   *   Layout builder section storage manager.
+   */
+  protected function getSectionStorageManager() {
--- a/src/ToolbarHandler.php
+++ b/src/ToolbarHandler.php
   *   The entity type manager.
   */
  public function __construct(
    ModuleHandlerInterface $module_handler,
--- a/environment_indicator.module
+++ b/environment_indicator.module
 * Implements hook_preprocess_HOOK() for page templates.
 */
 function environment_indicator_preprocess_html(&$variables) {
  if (_environment_indicator_external_integration_is_enabled('toolbar')) {
-  if (_environment_indicator_external_integration_is_enabled('toolbar')) {
+  if (_environment_indicator_external_integration_is_enabled('toolbar') || _environment_indicator_external_integration_is_enabled('navigation')) {
--- a/environment_indicator.module
+++ b/environment_indicator.module
    ->getStorage('environment_indicator')
    ->load($environment_id);
 }
+
+/**
+ * Implements hook_plugin_filter_block__layout_builder_alter().
+ *
+ * Curate the blocks available in the Layout Builder "Add Block" UI.
+ */
+function environment_indicator_plugin_filter_block__layout_builder_alter(array &$definitions, array $extra) {