"FirePHP extends FireBug functionalities to show log or error messages coming from your PHP application. These messages won’t be printed on the application interface but instead on the FireBug console."
"FireQuery is a Firefox addon integrated with Firebug. jQuery expressions are intelligently presented in Firebug Console and DOM inspector. Attached jQuery datas are first class citizens. Elements in jQuery collections are highlighted on hover. jQuerify: enables you to inject jQuery into any web page"
"Page Speed is an open-source Firefox/Firebug Add-on. Webmasters and web developers can use Page Speed to evaluate the performance of their web pages and to get suggestions on how to improve them."
"There are various add-ons that can add more power to Firebug for creating better & faster."