“The HTML5 specification brings several new elements to web developers allowing them to describe the structure of a web document with standard semantics. This document describes these elements and how to use them to define the desired outline for any document.”
http://slides.liip.ch/static/2012-05-18_symfony-speed.html A demo project to explain symfony2 frontend optimizations step by step. Each branch represents an optimization. See the project wiki for explanation about the branches