Update to Drupal 8.0-dev-2015-11-17. Commits through da81cd220, Tue Nov 17 15:53:49 2015 +0000, Issue #2617224 by Wim Leers: Move around/fix some documentation.

core/themes/stable/templates/admin/admin-block.html.twig

@@ -0,0 +1,24 @@
+{#
+/**
+ * @file
+ * Theme override for an administrative block.
+ *
+ * Available variables:
+ * - block: An array of information about the block, including:
+ *   - show: A flag indicating if the block should be displayed.
+ *   - title: The block title.
+ *   - content: (optional) The content of the block.
+ *   - description: (optional) A description of the block.
+ *     (Description should only be output if content is not available).
+ */
+#}
+<div class="panel">
+  {% if block.title %}
+    <h3 class="panel__title">{{ block.title }}</h3>
+  {% endif %}
+  {% if block.content %}
+    <div class="panel__content">{{ block.content }}</div>
+  {% elseif block.description %}
+    <div class="panel__description">{{ block.description }}</div>
+  {% endif %}
+</div>