from the jsAPI help
Flash MX 2004.
The library object represents the Library panel. It is a property of the Document object (see document.library) and can be accessed by fl.getDocumentDOM().library.
The library object contains an array of items of different types, including symbols, bitmaps, sounds, and video.
Property summary for the library object
The following property is available for the library object.
An array of item objects in the library