diff --git a/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockTypeTest.php b/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockTypeTest.php
index 8179e80..18e55df 100644
--- a/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockTypeTest.php
+++ b/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockTypeTest.php
@@ -171,7 +171,7 @@ public function testsCustomBlockAddTypes() {
         // The seven theme has markup inside the link, we cannot use clickLink().
         if ($default_theme == 'seven') {
           $options = $theme != $default_theme ? array('query' => array('theme' => $theme)) : array();
-          $this->assertLinkByHref(url('block/add/foo'));
+          $this->assertLinkByHref(url('block/add/foo', $options));
           $this->drupalGet('block/add/foo', $options);
         }
         else {
diff --git a/core/modules/system/templates/image.html.twig b/core/modules/system/templates/image.html.twig
new file mode 100644
index 0000000..b6b238a
--- /dev/null
+++ b/core/modules/system/templates/image.html.twig
@@ -0,0 +1,14 @@
+{#
+/**
+ * @file
+ * Default theme implementation of an image.
+ *
+ * Available variables:
+ * - attributes: HTML attributes for the img tag.
+ *
+ * @see template_preprocess_image()
+ *
+ * @ingroup themeable
+ */
+#}
+<img{{ attributes }} />
diff --git a/core/themes/seven/seven.theme b/core/themes/seven/seven.theme
index bce8664..58abfc0 100644
--- a/core/themes/seven/seven.theme
+++ b/core/themes/seven/seven.theme
@@ -6,6 +6,8 @@
  */
 
 use Drupal\Core\Template\RenderWrapper;
+use Drupal\Component\Utility\String;
+use Drupal\Component\Utility\Xss;
 
 /**
  * Implements hook_library_info().
@@ -48,8 +50,8 @@ function seven_preprocess_page(&$variables) {
 function seven_preprocess_node_add_list(&$variables) {
   if (!empty($variables['content'])) {
     foreach ($variables['content'] as $type) {
-      $variables['types'][$type->type]['label'] = check_plain($type->name);
-      $variables['types'][$type->type]['description'] = filter_xss_admin($type->description);
+      $variables['types'][$type->type]['label'] = String::checkPlain($type->name);
+      $variables['types'][$type->type]['description'] = Xss::filterAdmin($type->description);
       $variables['types'][$type->type]['path'] = url('node/add/' . $type->type);
     }
   }
@@ -67,9 +69,9 @@ function seven_preprocess_node_add_list(&$variables) {
 function seven_preprocess_custom_block_add_list(&$variables) {
   if (!empty($variables['content'])) {
     foreach ($variables['content'] as $id => $type) {
-      $variables['types'][$id]['label'] = check_plain($type->label());
-      $variables['types'][$id]['description'] = filter_xss_admin($type->description);
-      $variables['types'][$id]['path'] = url('block/add/' . $type->id);
+      $variables['types'][$id]['label'] = String::checkPlain($type->label());
+      $variables['types'][$id]['description'] = Xss::filterAdmin($type->description);
+      $variables['types'][$id]['path'] = \Drupal::l(String::checkPlain($type->name()), 'custom_block.add_form', array('custom_block_type' => $id), $options);
     }
   }
 }
@@ -83,9 +85,9 @@ function seven_preprocess_admin_block_content(&$variables) {
   if (!empty($variables['content'])) {
     $variables['compact'] = system_admin_compact_mode() ? 'compact' : '';
     foreach ($variables['content'] as $key => $item) {
-      $variables['content'][$key]['label'] = filter_xss_admin($item['title']);
+      $variables['content'][$key]['label'] = Xss::filterAdmin($item['title']);
       $variables['content'][$key]['path'] = url($item['href']);
-      $variables['content'][$key]['description'] = filter_xss_admin($item['description']);
+      $variables['content'][$key]['description'] = Xss::filterAdmin($item['description']);
     }
   }
 }
diff --git a/core/themes/seven/templates/node-add-list.html.twig b/core/themes/seven/templates/node-add-list.html.twig
index 9886e2f..dacbbd6 100644
--- a/core/themes/seven/templates/node-add-list.html.twig
+++ b/core/themes/seven/templates/node-add-list.html.twig
@@ -21,5 +21,7 @@
     {% endfor %}
   </ul>
 {% else %}
-  <p>{{ 'You have not created any content types yet. Go to the <a href="@create-content">content type creation page</a> to add a new content type.'|t({'@create-content': url('admin/structure/types/add')}) }}</p>
+  {% trans %}
+    <p>{{ 'You have not created any content types yet. Go to the <a href="@create-content">content type creation page</a> to add a new content type.'|t({'@create-content': url('admin/structure/types/add')}) }}</p>
+  {% endtrans %}
 {% endif %}