Package Layout

The Python X Library is distrubuted as a Python package, named Xlib. It contains a number of modules providing the main library interface:

display: Contains the Display class, providing the X connection and access to all other X objects and operations.
error: Contains all Xlib exception classes.
threaded: Imported to set up the library to be thread-safe.
rdb: Contains ResourceDB, an X resource database class, and related code.
X: Contains symbolic names for all basic X protocol constants.
Xutil: Contains additional constants for mainly the ICCCM standard.
XK: Contains symbolic names for all X keysyms.
Xatom: Contains symbolic names for all standard X atoms.
Xcursorfont: Contains symbolic names for all standard X fonts.

There is also a number of subpackages, but they will mainly be of interest to developers of the Xlib itself:

protocol: The low-level protocol implementation. Contains definitions of all X request, responses, events and errors, in addition to the core network code. The high-level object oriented interface provided by Xlib.display is merely a wrapper around this package.
support: Miscellaneous supporting code for handling threads and operating system-specific features.
xobject: Contains classes for all X objects, which are returned by various display operations.
ext: Contains various X protocol extensions. Extensions supported by the server are loaded automatically at the display connection.