This is a must-have plugin for all WordPress developers! Make sure you install it in your development environment.
One of the great things about developing for WordPress is the number of tools available for developers. WordPress core ships with a bunch of useful features (e.g. WP_DEBUG) with many more built by the community (like our own Rewrite Rules Inspector and VIP Scanner) that make development and debugging a breeze. The hardest part is getting your environment set up just right: knowing what constants to set, what plugins to install, and so on.