Tip: This course is built on Symfony 2, but most of the concepts apply just fine to Symfony 3.
Let's not just use Symfony, let's conquer it! In this series, you and I will journey to the center of Symfony by ripping open the source code, adding debug statements and seeing what really happens between the request and the response. It's as geeky-awesome as it sounds.
Besides dinosaurs, expect to do the following on our adventure:
HttpKernel::handle()method that's used in Symfony and Drupal 8
kernel.responseand others are dispatched