Low-level core library that forms the basis for projects such as GTK+ and GNOME.
An easy-to-use and general-purpose text editor since 1998
AbiWord is a cross-platform word processor. Integrates with GNOME.
Some examples for a talk
The GNOME text editor
GNOME Translation Editor
📗 libgirepository API docs
GNOME likes to cook
MineCraft, but better (and FOSS!)