Are you looking to learn more about the inner workings of Firefox? This short course will take you there by exploring the structure of the Firefox browser, the manual configuration of preferences (about:config), the anatomy of an extension (LibX, XUL, Javascript, Chrome, etc.), and developer resources. This session is for the users that truly wish to "get under the hood" of the Firefox browser. Like Part One, hands-on activities will be an essential component of this short course.