diff --git a/core/includes/batch.inc b/core/includes/batch.inc
index 786ee3c..68fc14b 100644
--- a/core/includes/batch.inc
+++ b/core/includes/batch.inc
@@ -165,7 +165,7 @@ function _batch_progress_page() {
     '#message' => $message,
     '#label' => $label,
     '#attached' => array(
-      'drupal_add_html_head' => array(
+      'html_head' => array(
         array(
           array(
             // Redirect through a 'Refresh' meta tag if JavaScript is disabled.
diff --git a/core/includes/common.inc b/core/includes/common.inc
index 1307f5e..e2ef676 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -198,7 +198,7 @@ function drupal_get_profile() {
  * @deprecated in Drupal 8.0.x, will be removed before Drupal 8.0.0
  *   Use #attached on render arrays.
  */
-function drupal_add_html_head($data = NULL, $key = NULL) {
+function _drupal_add_html_head($data = NULL, $key = NULL) {
   $stored_head = &drupal_static(__FUNCTION__, array());
 
   if (isset($data) && isset($key)) {
@@ -223,7 +223,7 @@ function drupal_add_html_head($data = NULL, $key = NULL) {
  *   Use #attached on render arrays.
  */
 function drupal_get_html_head($render = TRUE) {
-  $elements = drupal_add_html_head();
+  $elements = _drupal_add_html_head();
   \Drupal::moduleHandler()->alter('html_head', $elements);
   if ($render) {
     return drupal_render($elements);
@@ -246,7 +246,7 @@ function drupal_get_html_head($render = TRUE) {
  * @deprecated in Drupal 8.0.x, will be removed before Drupal 8.0.0
  *   Use #attached on render arrays.
  */
-function drupal_add_feed($url = NULL, $title = '') {
+function _drupal_add_feed($url = NULL, $title = '') {
   $stored_feed_links = &drupal_static(__FUNCTION__, array());
 
   if (isset($url)) {
@@ -262,7 +262,7 @@ function drupal_add_feed($url = NULL, $title = '') {
  *   Use #attached on render arrays.
  */
 function drupal_get_feeds() {
-  $feeds = drupal_add_feed();
+  $feeds = _drupal_add_feed();
   return $feeds;
 }
 
@@ -881,7 +881,7 @@ function base_path() {
  * @deprecated in Drupal 8.0.x, will be removed before Drupal 8.0.0
  *   Use #attached on render arrays.
  */
-function drupal_add_html_head_link($attributes, $header = FALSE) {
+function _drupal_add_html_head_link($attributes, $header = FALSE) {
   $element = array(
     '#tag' => 'link',
     '#attributes' => $attributes,
@@ -892,10 +892,10 @@ function drupal_add_html_head_link($attributes, $header = FALSE) {
     // Also add a HTTP header "Link:".
     $href = '<' . String::checkPlain($attributes['href']) . '>;';
     unset($attributes['href']);
-    $element['#attached']['drupal_add_http_header'][] = array('Link',  $href . drupal_http_header_attributes($attributes), TRUE);
+    $element['#attached']['http_header'][] = array('Link',  $href . drupal_http_header_attributes($attributes), TRUE);
   }
 
-  drupal_add_html_head($element, 'drupal_add_html_head_link:' . $attributes['rel'] . ':' . $href);
+  _drupal_add_html_head($element, 'html_head_link:' . $attributes['rel'] . ':' . $href);
 }
 
 /**
@@ -1868,7 +1868,27 @@ function drupal_process_attached($elements, $dependency_check = FALSE) {
   // special handling.
   foreach ($elements['#attached'] as $callback => $options) {
     foreach ($elements['#attached'][$callback] as $args) {
-      call_user_func_array($callback, $args);
+      // Limit the amount allowed entries.
+      switch ($callback) {
+        case '_drupal_add_html_head':
+        case 'html_head':
+          call_user_func_array('_drupal_add_html_head', $args);
+          break;
+        case '_drupal_add_feed':
+        case 'feed':
+          call_user_func_array('_drupal_add_feed', $args);
+          break;
+        case '_drupal_add_html_head_link':
+        case 'html_head_link':
+          call_user_func_array('_drupal_add_html_head_link', $args);
+          break;
+        case 'drupal_add_http_header':
+        case 'http_header':
+          call_user_func_array('drupal_add_http_header', $args);
+          break;
+        default:
+          throw new \LogicException(sprintf('You are not allowed to use %s in #attached', $callback));
+      }
     }
   }
 
diff --git a/core/includes/install.core.inc b/core/includes/install.core.inc
index 3c8d1216..7cfc943 100644
--- a/core/includes/install.core.inc
+++ b/core/includes/install.core.inc
@@ -904,7 +904,7 @@ function install_display_output($output, $install_state) {
       'content' => 'noindex, nofollow',
     ),
   );
-  drupal_add_html_head($noindex_meta_tag, 'install_meta_robots');
+  $output['#attached']['html_head'][] = [$noindex_meta_tag, 'install_meta_robots'];
 
   // Only show the task list if there is an active task; otherwise, the page
   // request has ended before tasks have even been started, so there is nothing
diff --git a/core/lib/Drupal/Core/Page/RenderHtmlRenderer.php b/core/lib/Drupal/Core/Page/RenderHtmlRenderer.php
index f3c166c..9358e25 100644
--- a/core/lib/Drupal/Core/Page/RenderHtmlRenderer.php
+++ b/core/lib/Drupal/Core/Page/RenderHtmlRenderer.php
@@ -52,23 +52,32 @@ public function render(array $render_array) {
 
     $attached = isset($render_array['#attached']) ? $render_array['#attached'] : [];
     $attached += [
-      'drupal_add_feed' => [],
-      'drupal_add_html_head' => [],
-      'drupal_add_html_head_link' => [],
+      '_drupal_add_feed' => [],
+      'feed' => [],
+      '_drupal_add_html_head' => [],
+      'html_head' => [],
+      '_drupal_add_html_head_link' => [],
+      'html_head_link' => [],
     ];
 
 
     // Add feed links from the page content.
-    foreach ($attached['drupal_add_feed'] as $feed) {
+    foreach ($attached['feed'] as $feed) {
+      $fragment->addLinkElement(new FeedLinkElement($feed[1], $this->urlGenerator->generateFromPath($feed[0])));
+    }
+    foreach ($attached['_drupal_add_feed'] as $feed) {
       $fragment->addLinkElement(new FeedLinkElement($feed[1], $this->urlGenerator->generateFromPath($feed[0])));
     }
 
     // Add generic links from the page content.
-    foreach ($attached['drupal_add_html_head_link'] as $link) {
+    foreach ($attached['_drupal_add_html_head_link'] as $link) {
+      $fragment->addLinkElement(new LinkElement($this->urlGenerator->generateFromPath($link[0]['href']), $link[0]['rel']));
+    }
+    foreach ($attached['html_head_link'] as $link) {
       $fragment->addLinkElement(new LinkElement($this->urlGenerator->generateFromPath($link[0]['href']), $link[0]['rel']));
     }
 
-    // @todo Also transfer the contents of "drupal_add_html_head" once
+    // @todo Also transfer the contents of "_drupal_add_html_head" once
     // https://www.drupal.org/node/2296951 lands.
 
     // @todo Transfer CSS and JS over to the fragment once those are supported
diff --git a/core/modules/aggregator/src/Controller/AggregatorController.php b/core/modules/aggregator/src/Controller/AggregatorController.php
index a37a81d..0cede69 100644
--- a/core/modules/aggregator/src/Controller/AggregatorController.php
+++ b/core/modules/aggregator/src/Controller/AggregatorController.php
@@ -176,7 +176,7 @@ public function adminOverview() {
   public function pageLast() {
     $items = $this->entityManager()->getStorage('aggregator_item')->loadAll(20);
     $build = $this->buildPageList($items);
-    $build['#attached']['drupal_add_feed'][] = array('aggregator/rss', $this->config('system.site')->get('name') . ' ' . $this->t('aggregator'));
+    $build['#attached']['feed'][] = array('aggregator/rss', $this->config('system.site')->get('name') . ' ' . $this->t('aggregator'));
     return $build;
   }
 
diff --git a/core/modules/book/book.module b/core/modules/book/book.module
index 6b631c7..8474f04 100644
--- a/core/modules/book/book.module
+++ b/core/modules/book/book.module
@@ -405,7 +405,7 @@ function template_preprocess_book_navigation(&$variables) {
 
     if ($prev = $book_outline->prevLink($book_link)) {
       $prev_href = \Drupal::url('entity.node.canonical', array('node' => $prev['nid']));
-      $build['#attached']['drupal_add_html_head_link'][][] = array(
+      $build['#attached']['html_head_link'][][] = array(
         'rel' => 'prev',
         'href' => $prev_href,
       );
@@ -417,7 +417,7 @@ function template_preprocess_book_navigation(&$variables) {
     $book_manager = \Drupal::service('book.manager');
     if ($book_link['pid'] && $parent = $book_manager->loadBookLink($book_link['pid'])) {
       $parent_href = \Drupal::url('entity.node.canonical', array('node' => $book_link['pid']));
-      $build['#attached']['drupal_add_html_head_link'][][] = array(
+      $build['#attached']['html_head_link'][][] = array(
         'rel' => 'up',
         'href' => $parent_href,
       );
@@ -427,7 +427,7 @@ function template_preprocess_book_navigation(&$variables) {
 
     if ($next = $book_outline->nextLink($book_link)) {
       $next_href = \Drupal::url('entity.node.canonical', array('node' => $next['nid']));
-      $build['#attached']['drupal_add_html_head_link'][][] = array(
+      $build['#attached']['html_head_link'][][] = array(
         'rel' => 'next',
         'href' => $next_href,
       );
diff --git a/core/modules/content_translation/content_translation.module b/core/modules/content_translation/content_translation.module
index 102c67a..55a19ba 100644
--- a/core/modules/content_translation/content_translation.module
+++ b/core/modules/content_translation/content_translation.module
@@ -745,7 +745,7 @@ function content_translation_page_alter(&$page) {
           ->setOption('language', $language)
           ->setAbsolute()
           ->toString();
-        $page['#attached']['drupal_add_html_head_link'][] = array(
+        $page['#attached']['html_head_link'][] = array(
           array(
             'rel' => 'alternate',
             'hreflang' => $language->id,
diff --git a/core/modules/forum/src/Controller/ForumController.php b/core/modules/forum/src/Controller/ForumController.php
index 5de156c..2ca2e8e 100644
--- a/core/modules/forum/src/Controller/ForumController.php
+++ b/core/modules/forum/src/Controller/ForumController.php
@@ -145,7 +145,7 @@ protected function build($forums, TermInterface $term, $topics = array(), $paren
     );
     $build['#attached']['library'][] = 'forum/forum.index';
     if (empty($term->forum_container->value)) {
-      $build['#attached']['drupal_add_feed'][] = array('taxonomy/term/' . $term->id() . '/feed', 'RSS - ' . $term->getName());
+      $build['#attached']['feed'][] = array('taxonomy/term/' . $term->id() . '/feed', 'RSS - ' . $term->getName());
     }
 
     return $build;
diff --git a/core/modules/node/src/Controller/NodePreviewController.php b/core/modules/node/src/Controller/NodePreviewController.php
index 35c65d9..2134abe 100644
--- a/core/modules/node/src/Controller/NodePreviewController.php
+++ b/core/modules/node/src/Controller/NodePreviewController.php
@@ -33,7 +33,7 @@ public function view(EntityInterface $node_preview, $view_mode_id = 'full', $lan
 
     foreach ($node_preview->uriRelationships() as $rel) {
       // Set the node path as the canonical URL to prevent duplicate content.
-      $build['#attached']['drupal_add_html_head_link'][] = array(
+      $build['#attached']['html_head_link'][] = array(
         array(
         'rel' => $rel,
         'href' => $node_preview->url($rel),
@@ -42,7 +42,7 @@ public function view(EntityInterface $node_preview, $view_mode_id = 'full', $lan
 
       if ($rel == 'canonical') {
         // Set the non-aliased canonical path as a default shortlink.
-        $build['#attached']['drupal_add_html_head_link'][] = array(
+        $build['#attached']['html_head_link'][] = array(
           array(
             'rel' => 'shortlink',
             'href' => $node_preview->url($rel, array('alias' => TRUE)),
diff --git a/core/modules/node/src/Controller/NodeViewController.php b/core/modules/node/src/Controller/NodeViewController.php
index 84559a5..2e68391 100644
--- a/core/modules/node/src/Controller/NodeViewController.php
+++ b/core/modules/node/src/Controller/NodeViewController.php
@@ -27,7 +27,7 @@ public function view(EntityInterface $node, $view_mode = 'full', $langcode = NUL
 
     foreach ($node->uriRelationships() as $rel) {
       // Set the node path as the canonical URL to prevent duplicate content.
-      $build['#attached']['drupal_add_html_head_link'][] = array(
+      $build['#attached']['html_head_link'][] = array(
         array(
           'rel' => $rel,
           'href' => $node->url($rel),
@@ -37,7 +37,7 @@ public function view(EntityInterface $node, $view_mode = 'full', $langcode = NUL
 
       if ($rel == 'canonical') {
         // Set the non-aliased canonical path as a default shortlink.
-        $build['#attached']['drupal_add_html_head_link'][] = array(
+        $build['#attached']['html_head_link'][] = array(
           array(
             'rel' => 'shortlink',
             'href' => $node->url($rel, array('alias' => TRUE)),
diff --git a/core/modules/rdf/rdf.module b/core/modules/rdf/rdf.module
index f407e83..4308e8e 100644
--- a/core/modules/rdf/rdf.module
+++ b/core/modules/rdf/rdf.module
@@ -367,7 +367,9 @@ function rdf_preprocess_user(&$variables) {
           'lang' => '',
         ),
       );
-      drupal_add_html_head($username_meta, 'rdf_user_username');
+      // @todo Convert once https://www.drupal.org/node/2346369 is in.
+      $build['#attached']['html_head'][] = [$username_meta, 'rdf_user_username'];
+      drupal_render($build);
     }
   }
 }
diff --git a/core/modules/system/src/Tests/Common/AddFeedTest.php b/core/modules/system/src/Tests/Common/AddFeedTest.php
index a24581d..3b495b3 100644
--- a/core/modules/system/src/Tests/Common/AddFeedTest.php
+++ b/core/modules/system/src/Tests/Common/AddFeedTest.php
@@ -12,13 +12,13 @@
 use Drupal\simpletest\WebTestBase;
 
 /**
- * Make sure that drupal_add_feed() works correctly with various constructs.
+ * Make sure that _drupal_add_feed() works correctly with various constructs.
  *
  * @group Common
  */
 class AddFeedTest extends WebTestBase {
   /**
-   * Tests drupal_add_feed() with paths, URLs, and titles.
+   * Tests _drupal_add_feed() with paths, URLs, and titles.
    */
   function testBasicFeedAddNoTitle() {
     $path = $this->randomMachineName(12);
@@ -29,10 +29,10 @@ function testBasicFeedAddNoTitle() {
     $external_for_title = 'http://' . $this->randomMachineName(12) . '/' . $this->randomMachineName(12);
     $fully_qualified_for_title = _url($this->randomMachineName(12), array('absolute' => TRUE));
 
-    // Possible permutations of drupal_add_feed() to test.
-    // - 'input_url': the path passed to drupal_add_feed(),
+    // Possible permutations of _drupal_add_feed() to test.
+    // - 'input_url': the path passed to _drupal_add_feed(),
     // - 'output_url': the expected URL to be found in the header.
-    // - 'title' == the title of the feed as passed into drupal_add_feed().
+    // - 'title' == the title of the feed as passed into _drupal_add_feed().
     $urls = array(
       'path without title' => array(
         'url' => _url($path, array('absolute' => TRUE)),
diff --git a/core/modules/system/src/Tests/Common/RenderTest.php b/core/modules/system/src/Tests/Common/RenderTest.php
index d07085c..4a6e2ba 100644
--- a/core/modules/system/src/Tests/Common/RenderTest.php
+++ b/core/modules/system/src/Tests/Common/RenderTest.php
@@ -1155,4 +1155,20 @@ protected function randomContextValue() {
     return $tokens[mt_rand(0, 4)];
   }
 
+  /**
+   * Tests drupal_process_attached().
+   */
+  public function testDrupalProcessAttached() {
+    // Specify an invalid render array.
+    $build['#attached']['library'][] = 'core/drupal.states';
+    $build['#attached']['drupal_process_states'][] = [];
+    try {
+      drupal_process_attached($build);
+      $this->fail("Invalid #attachmend 'drupal_process_states' allowed");
+    }
+    catch (\Exception $e) {
+      $this->pass("Invalid #attachmend 'drupal_process_states' not allowed");
+    }
+  }
+
 }
diff --git a/core/modules/taxonomy/taxonomy.module b/core/modules/taxonomy/taxonomy.module
index a715c0a..f17b105 100644
--- a/core/modules/taxonomy/taxonomy.module
+++ b/core/modules/taxonomy/taxonomy.module
@@ -110,7 +110,7 @@ function taxonomy_page_build(&$page) {
   if ($route_match->getRouteName() == 'entity.taxonomy_term.canonical' && ($term = $route_match->getParameter('taxonomy_term')) && $term instanceof TermInterface) {
     foreach ($term->uriRelationships() as $rel) {
       // Set the URI relationships, like canonical.
-      $page['#attached']['drupal_add_html_head_link'][] = array(
+      $page['#attached']['html_head_link'][] = array(
         array(
           'rel' => $rel,
           'href' => $term->url($rel),
@@ -121,7 +121,7 @@ function taxonomy_page_build(&$page) {
       // Set the term path as the canonical URL to prevent duplicate content.
       if ($rel == 'canonical') {
         // Set the non-aliased canonical path as a default shortlink.
-        $page['#attached']['drupal_add_html_head_link'][] = array(
+        $page['#attached']['html_head_link'][] = array(
           array(
             'rel' => 'shortlink',
             'href' => $term->url($rel, array('alias' => TRUE)),
diff --git a/core/modules/views/src/Plugin/views/cache/CachePluginBase.php b/core/modules/views/src/Plugin/views/cache/CachePluginBase.php
index 068197c..250ab84 100644
--- a/core/modules/views/src/Plugin/views/cache/CachePluginBase.php
+++ b/core/modules/views/src/Plugin/views/cache/CachePluginBase.php
@@ -231,10 +231,10 @@ public function postRender(&$output) { }
    * duplicate it. Later on, when gatherHeaders() is run, this information
    * will be removed so that we don't hold onto it.
    *
-   * @see drupal_add_html_head()
+   * @see _drupal_add_html_head()
    */
   public function cacheStart() {
-    $this->storage['head'] = drupal_add_html_head();
+    $this->storage['head'] = _drupal_add_html_head();
   }
 
   /**
@@ -246,7 +246,7 @@ public function cacheStart() {
   protected function gatherHeaders(array $render_array = []) {
     // Simple replacement for head
     if (isset($this->storage['head'])) {
-      $this->storage['head'] = str_replace($this->storage['head'], '', drupal_add_html_head());
+      $this->storage['head'] = str_replace($this->storage['head'], '', _drupal_add_html_head());
     }
     else {
       $this->storage['head'] = '';
@@ -261,7 +261,7 @@ protected function gatherHeaders(array $render_array = []) {
    */
   public function restoreHeaders() {
     if (!empty($this->storage['head'])) {
-      drupal_add_html_head($this->storage['head']);
+      _drupal_add_html_head($this->storage['head']);
     }
     if (!empty($this->storage['css'])) {
       foreach ($this->storage['css'] as $args) {
diff --git a/core/modules/views/src/Plugin/views/style/Opml.php b/core/modules/views/src/Plugin/views/style/Opml.php
index ad23aae..229e4c2 100644
--- a/core/modules/views/src/Plugin/views/style/Opml.php
+++ b/core/modules/views/src/Plugin/views/style/Opml.php
@@ -44,7 +44,7 @@ public function attachTo(array &$build, $display_id, $path, $title) {
     $url = _url($this->view->getUrl(NULL, $path), $url_options);
     if ($display->hasPath()) {
       if (empty($this->preview)) {
-        $build['#attached']['drupal_add_feed'][] = array($url, $title);
+        $build['#attached']['feed'][] = array($url, $title);
       }
     }
     else {
diff --git a/core/modules/views/src/Plugin/views/style/Rss.php b/core/modules/views/src/Plugin/views/style/Rss.php
index 99dc0c3..366deae 100644
--- a/core/modules/views/src/Plugin/views/style/Rss.php
+++ b/core/modules/views/src/Plugin/views/style/Rss.php
@@ -44,8 +44,8 @@ public function attachTo(array &$build, $display_id, $path, $title) {
     $url = _url($this->view->getUrl(NULL, $path), $url_options);
     if ($display->hasPath()) {
       if (empty($this->preview)) {
-        // Add a call for drupal_add_feed to the view attached data.
-        $build['#attached']['drupal_add_feed'][] = array($url, $title);
+        // Add a call for _drupal_add_feed to the view attached data.
+        $build['#attached']['feed'][] = array($url, $title);
       }
     }
     else {
@@ -56,8 +56,8 @@ public function attachTo(array &$build, $display_id, $path, $title) {
       );
       $this->view->feed_icon = $feed_icon;
 
-      // Add a call for drupal_add_html_head_link to the view attached data.
-      $build['#attached']['drupal_add_html_head_link'][][] = array(
+      // Add the RSS icon to the view.
+      $build['#attached']['html_head_link'][][] = array(
         'rel' => 'alternate',
         'type' => 'application/rss+xml',
         'title' => $title,