diff --git a/core/themes/seven/seven.theme b/core/themes/seven/seven.theme
index 43f6f80..d2a3992 100644
--- a/core/themes/seven/seven.theme
+++ b/core/themes/seven/seven.theme
@@ -127,26 +127,24 @@ function seven_preprocess_node_add_list(&$variables) {
 }
 
 /**
- * Implements hook_preprocess_HOOK() for custom block add list templates.
+ * Implements hook_preprocess_HOOK() for block content add list templates.
  *
  * Displays the list of available custom block types for creation, adding
  * separate variables for the label, description, and url.
  */
-function seven_preprocess_custom_block_add_list(&$variables) {
+function seven_preprocess_block_content_add_list(&$variables) {
   if (!empty($variables['content'])) {
     foreach ($variables['content'] as $type) {
       $variables['types'][$type->id()]['label'] = String::checkPlain($type->label());
       $variables['types'][$type->id()]['description'] = Xss::filterAdmin($type->description);
       $options = array('query' => \Drupal::request()->query->all());
-      $variables['types'][$type->id()]['url'] = \Drupal::url('custom_block.add_form', array('custom_block_type' => $type->id()), $options);
+      $variables['types'][$type->id()]['url'] = \Drupal::url('block_content.add_form', array('block_content_type' => $type->id()), $options);
     }
   }
 }
 
 /**
  * Implements hook_preprocess_HOOK() for block admin page templates.
- *
- * Uses an unordered list markup in both compact and extended mode.
  */
 function seven_preprocess_admin_block_content(&$variables) {
   if (!empty($variables['content'])) {
diff --git a/core/themes/seven/templates/admin-block-content.html.twig b/core/themes/seven/templates/admin-block-content.html.twig
index 175dc79..7dc0a92 100644
--- a/core/themes/seven/templates/admin-block-content.html.twig
+++ b/core/themes/seven/templates/admin-block-content.html.twig
@@ -3,10 +3,12 @@
  * @file
  * Seven's theme implementation for the content of an administrative block.
  *
+ * Uses unordered list markup in both compact and extended modes.
+ *
  * Available variables:
  * - content: List of administrative menu items. Each menu item contains:
  *   - url: Path to the admin section.
- *   - label: Short name of the section.
+ *   - title: Short name of the section.
  *   - description: Description of the administrative menu item.
  * - attributes: HTML attributes to be added to the element.
  *
@@ -17,7 +19,7 @@
 {% if content %}
   <ul{{ attributes }}>
     {% for item in content %}
-      <li><a href="{{ item.url }}"><span class="label">{{ item.label }}</span><div class="description">{{ item.description }}</div></a></li>
+      <li><a href="{{ item.url }}"><span class="label">{{ item.title }}</span><div class="description">{{ item.description }}</div></a></li>
     {% endfor %}
   </ul>
 {% endif %}
diff --git a/core/themes/seven/templates/custom-block-add-list.html.twig b/core/themes/seven/templates/block-content-add-list.html.twig
similarity index 75%
rename from core/themes/seven/templates/custom-block-add-list.html.twig
rename to core/themes/seven/templates/block-content-add-list.html.twig
index 02ba5cf..0c0c496 100644
--- a/core/themes/seven/templates/custom-block-add-list.html.twig
+++ b/core/themes/seven/templates/block-content-add-list.html.twig
@@ -1,21 +1,20 @@
 {#
 /**
  * @file
- * Overrides custom-block-add-list.html.twig.
+ * Seven's theme implementation to display a list of custom block types.
  *
  * Displays the list of available custom block types for creation.
  *
  * Available variables:
  * - types: A collection of all the available custom block types.
  *   Each type contains:
- *   - type: The custom block type, containing all the items below.
  *   - url: A link to add a block of this type.
  *   - description: A description of this custom block type.
  *   - label: The title of the custom block type.
  *   - path: A path for the link to add a block of this type.
  *
- * @see template_preprocess_custom_block_add_list()
- * @see seven_preprocess_custom_block_add_list()
+ * @see template_preprocess_block_content_add_list()
+ * @see seven_preprocess_block_content_add_list()
  */
  #}
 <ul class="admin-list">
diff --git a/core/themes/seven/templates/tablesort-indicator.html.twig b/core/themes/seven/templates/tablesort-indicator.html.twig
index 8aa40fa..b2eadaa 100644
--- a/core/themes/seven/templates/tablesort-indicator.html.twig
+++ b/core/themes/seven/templates/tablesort-indicator.html.twig
@@ -1,11 +1,12 @@
 {#
 /**
  * @file
- * Default theme implementation for displaying a tablesort indicator.
+ * Seven's theme implementation for displaying a tablesort indicator.
  *
  * Available variables:
  * - style: Either 'asc' or 'desc', indicating the sorting direction.
- * - theme_path: Path to the theme.
+ * - arrow_asc: URL to the image for an ascending arrow.
+ * - arrow_desc: URL to the image for a descending arrow.
  */
 #}
 {% if style == 'asc' -%}