Using PDT : Installation : Installing the Zend Debugger - PDTWiki

Using PDT : Installation : Installing the Zend Debugger - PDTWiki: "Zend Debugger is a full-featured php debugger engine. It is an interactive tool that allows you to debug PHP scripts locally or remotely, from an IDE or from the console.
To use the debugger engine you must install it to run in the PHP interpreter.
PDT has a built-in debugging client that operates the Zend debugging engine. The debugger client must be configured to communicate with the debugger engine. This is true for both the PDT all-in-one package or the PDT plugin only
Alternatively, if you want to debug only local PHP scripts, you may install the Zend Executable Debugger plug-in. The Zend Executable Debugger plug-in adds a local PHP 4 and PHP 5 binary ready for debugging. This is useful if you do not have a PHP binary locally or cannot use your local php binary because it is not suitable for debugging (depends on compile options, ...) or want to use this debugger without the PDT (with PHPEclipse, for example)."