diff --git a/core/lib/Drupal/Core/Plugin/Context/ContextHandler.php b/core/lib/Drupal/Core/Plugin/Context/ContextHandler.php
index efe7158..7a5e332 100644
--- a/core/lib/Drupal/Core/Plugin/Context/ContextHandler.php
+++ b/core/lib/Drupal/Core/Plugin/Context/ContextHandler.php
@@ -101,9 +101,9 @@ public function applyContextMapping(ContextAwarePluginInterface $plugin, $contex
       }
     }
 
-    // if there are any required contexts without a value, throw an exception.
+    // If there are any required contexts without a value, throw an exception.
     if ($missing_value) {
-      throw new ContextException(SafeMarkup::format("Required contexts without a value: @contexts.", array('@contexts' => implode(', ', $missing_value))));
+      throw new ContextException(sprintf('Required contexts without a value: %s.', implode(', ', $missing_value)));
     }
 
     // If there are any mappings that were not satisfied, throw an exception.
diff --git a/core/modules/system/tests/modules/condition_test/src/Plugin/Condition/OptionalContextCondition.php b/core/modules/system/tests/modules/condition_test/src/Plugin/Condition/OptionalContextCondition.php
index 986a66c..88c7d41 100644
--- a/core/modules/system/tests/modules/condition_test/src/Plugin/Condition/OptionalContextCondition.php
+++ b/core/modules/system/tests/modules/condition_test/src/Plugin/Condition/OptionalContextCondition.php
@@ -10,7 +10,10 @@
 use Drupal\Core\Condition\ConditionPluginBase;
 
 /**
- * Provides a condition with optional context.
+ * Provides a condition with an optional node context.
+ *
+ * The context type entity:node is used since that would allow to also use this
+ * for web tests with the node route context.
  *
  * @Condition(
  *   id = "condition_test_optional_context",