GObject.TYPE_POINTER
GObject.TYPE_POINTER represents the gpointer type in the GObject type system. You can pass this object to methods taking a GObject.Type.
A gpointer value is a generic untyped pointer (memory address). For memory safety reasons, gjs does not allow modifying pointers directly, so the only valid value for gpointer arguments is null (if allowed by the C function, otherwise the call is not available to JS code).
As a callback argument, a gpointer is implicitly skipped.