A pretty error-handling library.

A variable dumper component.

A debug and profile tool for PHP.

A debugging and profiling tool.

A profiling tool originally developed by Facebook.

A benchmarking Framework.

A simple error detection, logging and time measuring library.

A low-overhead sampling profiler.

Another web debugging console using Google Chrome.

A self-contained code coverage compatible driver.

A web debugging console.

A simple metrics API library.