diff --git a/core/lib/Drupal/Component/Utility/SafeMarkup.php b/core/lib/Drupal/Component/Utility/SafeMarkup.php
index 7ad3aa4..c0b8c22 100644
--- a/core/lib/Drupal/Component/Utility/SafeMarkup.php
+++ b/core/lib/Drupal/Component/Utility/SafeMarkup.php
@@ -186,10 +186,9 @@ public static function checkPlain($text) {
    *     @code
    *       <em class="placeholder">text output here.</em>
    *     @endcode
-   *   - ':variable': URL placeholder, escaped to HTML but also stripped of bad
-   *     protocols like "javascript:". This is the only placeholder that is
-   *     secure when placing a URL into an HTML attribute (such as "src" or
-   *     "href").
+   *   - ':variable': HTML is escaped and bad protocols like "javascript:" are
+   *     stripped. This is the only placeholder that is secure when placing a
+   *     URL into a HTML attribute (such as "src" or "href").
    *   - !variable: Inserted as is, with no sanitization or formatting. Only
    *     use this when the resulting string is being generated for one of:
    *     - Non-HTML usage, such as a plain-text email.
diff --git a/core/lib/Drupal/Core/DependencyInjection/DependencySerializationTrait.php b/core/lib/Drupal/Core/DependencyInjection/DependencySerializationTrait.php
index 4488e2b..14ca6cf 100644
--- a/core/lib/Drupal/Core/DependencyInjection/DependencySerializationTrait.php
+++ b/core/lib/Drupal/Core/DependencyInjection/DependencySerializationTrait.php
@@ -49,6 +49,8 @@ public function __sleep() {
    * {@inheritdoc}
    */
   public function __wakeup() {
+    // In PHPUnit tests we might want to use objects like \Drupal\Core\Url in
+    // data providers, which are executed before any setup code.
     if (!\Drupal::hasContainer()) {
       return;
     }
diff --git a/core/tests/Drupal/KernelTests/Component/Utility/SafeMarkupKernelTest.php b/core/tests/Drupal/KernelTests/Component/Utility/SafeMarkupKernelTest.php
index 8cdfbc9..29adbfb 100644
--- a/core/tests/Drupal/KernelTests/Component/Utility/SafeMarkupKernelTest.php
+++ b/core/tests/Drupal/KernelTests/Component/Utility/SafeMarkupKernelTest.php
@@ -14,7 +14,7 @@
 use Drupal\KernelTests\KernelTestBase;
 
 /**
- * Providers an integration test coverage for SafeMarkup with other systems.
+ * Provides a test covering integration of SafeMarkup with other systems.
  *
  * @group Utility
 */