You might be asking yourself how a debugger can help to improve software and its development process?
Many interesting insights can be found within this debugger: the idea was to present relevant information just when needed. Given variables are analysed and linked to their occurrences. Files can be browsed and opened directly into the debugger window for viewing and verifying that every file is at the right place. An integration of php_info() provides fast access to the system configuration and the possibility to inspect the installed modules. The request of your PHP script is described within the system area, where you can see every given parameter, so that you don't have to manually inspect each global variable.
These are only few features of the current debugger, but you can imagine how fast a developer can learn about the environment in which he is moving and deepen his insight on how PHP really works. Getting the information you need faster, will result in an improved development process!
A good quality can be reached, when errors and mistakes are identified in an early stage of development. The integrated error handler helps to identify minor and major bugs from the beginning. The content of a variable or the response of a function can be validated early, by inspecting them in the debugger.
Sure, it can't replace unit tests but it will improve the process to bring stable code into the tests, before they throw exceptions.
The integrated performance monitor keeps track of the memory used and of execution time. Every debugger event will cause a measuring point to be created, helping to analyse the executed PHP application from the initialisation to the output of your script. This makes it very easy to see how much resources your application needs and find potentially bottlenecks. The result is displayed within a diagram directly into your browser whenever your need.
Of course the debugger uses the same resources like your application, but the main load is addressed after your script was done.
This tool is developed to help constant code improvement and to identify potentially problems early.