GtdActivatable — entry point for plugins
GtdManager — bridge between plugins and GNOME To Do
GtdNotification — a notification with actions
GtdObject — base class for loadable and uniquely identifiable objects
GtdPanel — interface for panels
GtdProvider — data sources for GNOME To do
GtdTask — a task
GtdTaskList — a list of tasks
GtdTaskListView — A widget to display tasklists
GtdWindow — main window