Condensed in a single ~65KB file, F3 (as we fondly call it) gives you solid foundation, a mature code base, and a no-nonsense approach to writing Web applications. Under the hood is an easy-to-use Web development tool kit, a high-performance URL routing and cache engine, built-in code highlighting, and support for multilingual applications. It's lightweight, easy-to-use, and fast. Most of all, it doesn't get in your way.
Dontbug is a reverse debugger (aka time travel debugger) for PHP. It allows you to record the execution of PHP scripts (in command line mode or in the browser) and replay the same execution back in a PHP IDE debugger. During replay you may debug normally (forward mode debugging) or in reverse, which allows you to step over/out backwards, step backwards, run backwards, run to cursor backwards, set breakpoints in the past and so forth. Debugging with the ability to run in reverse allows you to hunt down bugs much more easily. It also allows you to understand the runtime behavior of large PHP codebases more efficiently.