diff --git a/core/modules/language/config/optional/tour.tour.language.yml b/core/modules/language/config/optional/tour.tour.language.yml
index 7cca3e5..ffc855d 100644
--- a/core/modules/language/config/optional/tour.tour.language.yml
+++ b/core/modules/language/config/optional/tour.tour.language.yml
@@ -34,7 +34,7 @@ tips:
     body: '<p>You can change the default language of the site by choosing one of your configured languages as default. The site will use the default language in situations where no choice is made but a language should be set, for example as the language of the displayed interface.</p>'
     weight: 4
     attributes:
-      data-class: form-item-site-default-language
+      data-class: js-form-item-site-default-language
   language-operations:
     id: language-operations
     plugin: text
diff --git a/core/modules/system/src/Tests/System/ThemeTest.php b/core/modules/system/src/Tests/System/ThemeTest.php
index d5bb6f6..d1ff7aa 100644
--- a/core/modules/system/src/Tests/System/ThemeTest.php
+++ b/core/modules/system/src/Tests/System/ThemeTest.php
@@ -95,7 +95,7 @@ function testThemeSettings() {
 
       // Verify logo path examples.
       $elements = $this->xpath('//div[contains(@class, :item)]/div[@class=:description]/code', array(
-        ':item' => 'form-item-logo-path',
+        ':item' => 'js-form-item-logo-path',
         ':description' => 'description',
       ));
       // Expected default values (if all else fails).