Properties

Libraries, lists, and media items all have properties accessible via the .getProperty() API.  .getProperty takes a property name and will contain metadata such as track name, artist name, duration, whether a playlist is editable or hidden, etc.

Songbird itself ships with a set of default properties.  Developers (using either the extension API, or Webpage API) can define new third-party properties.  Properties are defined using namespaces, with all the default Songbird ones namespaced at 'http://songbirdnest.com/data/1.0'.  The canonical list of Songbird stock properties is always available in sbStandardProperties.h

For extensions, an easy way to access the properties is to import sbProperties.jsm and use the SBProperties object:

Components.utils.import("resource://app/jsmodules/sbProperties.jsm");

alert(someItem.getProperty(SBProperties.trackName));