Components

There are two main parts to a Mozilla application. The XUL frontend, and the components in the backend.

Songbird components perform many tasks, including media related jobs like playback, playlist import, maintaining the media libraries, and so on. In addition to the Songbird developed components there are also many components we inherited from Mozilla, including all of Gecko and Necko, which are the rendering and network frameworks.  Components can also be provided by addons. Components are written in C++ or Javascript and are organized by XPCOM. See the Mozilla documentation for more details.