The MLWorks Motif interface library is not loaded into the interactive environment. It is supplied as a set of source and compiled files on disk, suitable for loading into the interactive environment or for building into your applications.
The Motif interface library provides an ML interface to the X Window System with Motif, including relevant parts of the X Toolkit, and to the graphics functionality of Xlib.
See Chapter 5, "The MLWorks Motif Interface Library", for more details.