commit 0dd0d55f751063b305576f37761d6e1a8c7a783b
Author: Joel Pittet <joel@pittet.ca>
Date:   Mon Feb 24 09:26:22 2014 -0800

    docs

diff --git a/core/modules/system/templates/container.html.twig b/core/modules/system/templates/container.html.twig
index 933a201..a643e19 100644
--- a/core/modules/system/templates/container.html.twig
+++ b/core/modules/system/templates/container.html.twig
@@ -3,6 +3,9 @@
  * @file
  * Default theme implementation of a container used to wrap child elements.
  *
+ * Used for grouped form items. Can also be used as a #theme_wrapper for any
+ * renderable element, to surround it with a <div> and HTML attributes.
+ *
  * Available variables:
  * - attributes: HTML attributes for the containing element.
  * - children: The rendered child elements of the container.