Move into nested docroot

web/core/modules/system/templates/details.html.twig

@@ -0,0 +1,39 @@
+{#
+/**
+ * @file
+ * Default theme implementation for a details element.
+ *
+ * Available variables
+ * - attributes: A list of HTML attributes for the details element.
+ * - errors: (optional) Any errors for this details element, may not be set.
+ * - title: (optional) The title of the element, may not be set.
+ * - description: (optional) The description of the element, may not be set.
+ * - children: (optional) The children of the element, may not be set.
+ * - value: (optional) The value of the element, may not be set.
+ *
+ * @see template_preprocess_details()
+ *
+ * @ingroup themeable
+ */
+#}
+<details{{ attributes }}>
+  {%
+    set summary_classes = [
+      required ? 'js-form-required',
+      required ? 'form-required',
+    ]
+  %}
+  {%- if title -%}
+    <summary{{ summary_attributes.addClass(summary_classes) }}>{{ title }}</summary>
+  {%- endif -%}
+
+  {% if errors %}
+    <div>
+      {{ errors }}
+    </div>
+  {% endif %}
+
+  {{ description }}
+  {{ children }}
+  {{ value }}
+</details>