Ray is a beautiful, lightweight desktop app that helps you debug your app. There’s a free demo available that can be unlocked with a license.
After installing this plugin, you can use the ray() function to quickly dump stuff. Any variable(s) that you pass to ray() will be displayed.
Here some examples:
ray('Hello world');
ray(['a' => 1, 'b' => 2])->color('red');
ray('multiple', 'arguments', 'are', 'welcome');
ray()->showQueries();
There are many other helper functions available on Ray that allow you to display things that can help you debug such as runtime and memory usage, queries that were executed, and much more.
Full Documentation
The extensive documentation can be found here.
It contains the installation instructions for WordPress.
After it is installed you can use any of the framework agnostic and WordPress specific functions.
This plugin is available for download to be used on your WordPress self-hosted installation.