Here you can find the instructions for installing Xdebug and Kcachegrind to profile and debug PHP applications.
Supposing that you’re using the penguin, with Debian or *buntu, there are a few steps ( very easy steps ) that you have to do in order to set up an environment which helps you on debugging PHP and profiling scripts.
It contains 160+ pages of content dedicated to securing web applications and improving your security awareness when building
web apps, with chapters ranging from explaining how to secure HTTP cookies with the right flags to understanding why it is
important to consider joining a bug bounty program.