Mark Conroy
--- a/core/profiles/demo_umami/tests/src/Functional/DemoUmamiProfileTest.php
+++ b/core/profiles/demo_umami/tests/src/Functional/DemoUmamiProfileTest.php
    // Check when editing a node, the warning is visible.
    $this->drupalGet($recipe_node->toUrl('edit-form'));
    $web_assert->statusCodeEquals(200);
-    $web_assert->pageTextContains('This site is intended for demonstration purposes.');
--- a/core/profiles/demo_umami/demo_umami.profile
+++ b/core/profiles/demo_umami/demo_umami.profile
-function demo_umami_toolbar() {
-  // Add a warning about using an experimental profile.
-  // @todo This can be removed once a generic warning for experimental profiles
-  //   has been introduced. https://www.drupal.org/project/drupal/issues/2934374
-  $items['experimental-profile-warning'] = [
-    '#weight' => 3400,
-    '#cache' => [
-      'contexts' => ['route'],
-    ],
-  ];
-
-  // Show warning only on administration pages.
+function demo_umami_preprocess_html(&$variables) {
+  // We want to make sure people know that Umami is only a demonstration of
+  // Drupal, and should not be used as a starterkit.
+  // To do so, we will show warning at the top of administration pages.
-  // To do so, we will show warning at the top of administration pages.
+  // To do so, we will show a warning at the top of administration pages.
--- a/core/profiles/demo_umami/demo_umami.profile
+++ b/core/profiles/demo_umami/demo_umami.profile
-    '#cache' => [
-      'contexts' => ['route'],
-    ],
-  ];
-
-  // Show warning only on administration pages.
+function demo_umami_preprocess_html(&$variables) {
+  // We want to make sure people know that Umami is only a demonstration of
+  // Drupal, and should not be used as a starterkit.
+  // To do so, we will show warning at the top of administration pages.
  $admin_context = \Drupal::service('router.admin_context');
  if ($admin_context->isAdminRoute()) {
    $link_to_help_page = \Drupal::moduleHandler()->moduleExists('help') && \Drupal::currentUser()->hasPermission('access help pages');
-    $items['experimental-profile-warning']['#type'] = 'toolbar_item';
-    $items['experimental-profile-warning']['tab'] = [
+    // Add this to the end of the page
-    // Add this to the end of the page
+    // Add this to the end of the page.
--- a/core/profiles/demo_umami/demo_umami.profile
+++ b/core/profiles/demo_umami/demo_umami.profile
-
-  // Show warning only on administration pages.
+function demo_umami_preprocess_html(&$variables) {
+  // We want to make sure people know that Umami is only a demonstration of
+  // Drupal, and should not be used as a starterkit.
+  // To do so, we will show warning at the top of administration pages.
  $admin_context = \Drupal::service('router.admin_context');
  if ($admin_context->isAdminRoute()) {
    $link_to_help_page = \Drupal::moduleHandler()->moduleExists('help') && \Drupal::currentUser()->hasPermission('access help pages');
-    $items['experimental-profile-warning']['#type'] = 'toolbar_item';
-    $items['experimental-profile-warning']['tab'] = [
+    // Add this to the end of the page
+    $variables['page_top'][] = [
      '#type' => 'inline_template',
-      '#template' => '<a class="toolbar-warning" href="{{ more_info_link }}">This site is intended for demonstration purposes.</a>',
+      '#template' => '<p class="demo-profile-warning"><a href="{{ more_info_link }}">This site is intended for demonstration purposes.</a></p>',