Debug Toolkit is a collection of utilities that simplifies the process of finding and fixing errors in PHP code, primarily for developers working on custom websites. It replaces basic, hard-to-read PHP outputs with interactive tools that provide clear insights into code behavior.

• Better Error Interface: Integrates the Whoops library to transform standard PHP error messages into an interactive page. This interface shows the problematic code, offers search links, and displays a clickable call stack with request details.
• Enhanced Variable Inspection: Offers two popular variable dumpers, VarDumper and Kint, as alternatives to var_dump or print_r. These tools format data clearly and can show data types, memory size, and the expression passed to them.
• Utility Functions: Provides a set of easy-to-use functions like dump(), vdump(), and their _and_die counterparts to output variable values directly in your code. Shorthand aliases like dd() and vd() are included for faster typing.
• Call Stack Tracing: Includes a trace() function to output the sequence of function calls leading to a specific point in your program. This can be combined with the dump functions for detailed analysis.
• Development-Only Indicator: Adds a 'DEBUG ACTIVE' notice to the admin bar as a visual reminder that the toolkit is enabled, which helps prevent accidentally leaving it active on a live site.