imathis/octopress — pull request #825 by davidagee (2012-11-27 20:24:08+00:00)
Title: Added hAtom microformatting to category_links filter

http://microformats.org/wiki/hatom (scroll to Entry Category)

Since these link to a category index page, the "directory" attribute
also applies:

http://microformats.org/wiki/rel-directory