D-Bus API
D-Bus is a system for interprocess communication (IPC).
GTK API
GTK (GIMP Toolkit) is a library for creating graphical user interfaces
Hildon API
Hildon application framework introduces a new desktop for handheld devices.
API documentation for Hildon Status bar, Home Applets and Navigator
API documentation for Hildon Control Panel
API documentation for python bindings for Hildon
This page lists the changes from old Hildon (the one included on maemo 3.0 release) to the new Hildon 2.0. The new API reference is here
API documentation for Python bindings for Libosso
Gnome Developer Documentation