twbs/bootstrap — pull request #9355 by kevinSuttle (2013-08-12 03:41:18+00:00)
Title: Map 'role="complementary"' to proper HTML5 aside element

http://blog.paciellogroup.com/2013/02/using-wai-aria-landmarks-2013/#tablex

http://www.w3.org/TR/wai-aria/roles#complementary