Linux System - Table 12 > Packages - Table 7 > XFree86

What XFree86 does, is provide a client/server interface between the display hardware (those physical things like the mouse, keyboard, and video displays) and the desktop environment, (this is typically called a window manager as it deals with how X is displayed i.e. the overall appearance). Yet X it goes beyond that and also gives the infrastructure and a standardized application interface (API).