Symfony is a reusable set of standalone, decoupled, and cohesive PHP 5.3 components that solve common web development problems. Symfony is also a full stack web framework. It is an Open Source software.
eZ Publish 5 uses Symfony2 in order to create website templates.
You can see the Requirements for installing/using Symfony by clicking on the following link: Installing Symfony - Requirements and Checks.
To download Symfony, go to www.symfony.com and click on the "Download Now" button. You will see the following page:
You can also find an extensive documentation about Symfony on the following link: Symfony Documentation.
