Нашел описание нового шаблона Blogger в Google Groups

Наконец-то. At every level of the HTML template you will find a common construct of elements that, for lack of a snappy name, I will term the “outer / cap / fauxborder / inner” construct, or OCBI. This set of elements will allow you to consistently apply various styling techniques to particular pieces of the template.

Для чего нужны fauxcolumns

code