defunkt/jquery-pjax — pull request #99 by squeedee (2012-02-27 22:13:46+00:00)
Title: Adding X-PJAX-Container header.

I find this useful. It lets the server discern the target container, and as such what 'level' of content that needs rednering into it. Usefull for sub navs and multple containers on a page.