Drupal 8.0.0 beta 12. More info: https://www.drupal.org/node/2514176

core/modules/system/templates/datetime-wrapper.html.twig

@@ -0,0 +1,32 @@
+{#
+/**
+ * @file
+ * Default theme implementation of a datetime form wrapper.
+ *
+ * Available variables:
+ * - content: The form element to be output, usually a datelist, or datetime.
+ * - title: The title of the form element.
+ * - title_attributes: HTML attributes for the title wrapper.
+ * - description: Description text for the form element.
+ * - required: An indicator for whether the associated form element is required.
+ *
+ * @see template_preprocess_datetime_wrapper()
+ *
+ * @ingroup themeable
+ */
+#}
+{%
+  set title_classes = [
+    required ? 'form-required',
+  ]
+%}
+{% if title %}
+  <h4{{ title_attributes.addClass(title_classes) }}>{{ title }}</h4>
+{% endif %}
+{{ content }}
+{% if errors %}
+  <div>
+    {{ errors }}
+  </div>
+{% endif %}
+{{ description }}