In a nutshell, Chrome is the user interface parts of the application window that are outside Mozilla products. The user interface is composed mostly of a window's content area. ToolbarsXUL, menu barsXBL, progress barsCSS, and window title bars JS files. Extensions are all examples (usually) chrome applets. 90% of elements that are an [http://developer.mozilla.org/en/docs/Extensions extension], typically part of the is chrome.

To make Mozilla modifiableIn the XUL world, you will first extract Chrome is the top level window which contains groups of UI files from the archives stored within elements of various types. Example of chrome are the browser window and dialog window. The chrome subdirectory obtains its UI description from four types of providers:  * Content provider::Provides the Mozilla installation directory with an unzip utilityskeleton, i. Use your unzip utility to extract all files in that directory with a e.jar extension. Make sure you extract them into , the menus, command buttons* Skin provider::Supplies the look-and-feel of the same (chrome) directory in which they are located.* Platform provider::Gives platform dependent UI description* Locale provider::Offers the language and culture sensitive resources