G-Golf GLib modules are defined in the glib subdirectory, such as
(g-golf glib main-event-loop).
Where you may load these modules individually, the easiest way to use G-Golf GLib is to import its main module, which imports and re-exports the public interface of (oop goops), (system foreign), all G-Golf support and G-Golf GLib modules:
(use-modules (g-golf glib))
G-Golf GLib low level API modules correspond to a GLib section, though they might be some exception in the future.