Have you ever wondered how super globals get initialized or been curious what happens before your code is turned into an http response? Have you ever wanted to add a new feature to PHP that you could deploy across all the applications hosted on a server? 20k Lines Under the C dives deep into the source of the PHP runtime, extension APIs, and parts that make it translate your code into web pages. We'll begin by looking at how web servers provide PHP the request information. We'll follow the startup process making stops along the way pointing out the internal structure and key parts during execution where various data is initialized and processed. Through this journey we'll learn about some of the special data types that PHP exposes and the APIs used to interact with them. Finally we'll explore the the different types of PHP integrations and explore how to insert hooks into just about everything providing ways to inspect and change the behavior.