The xcb-util module provides a number of libraries which sit on top of libxcb, the core X protocol library, and some of the extension libraries. These experimental libraries provide convenience functions and interfaces which make the raw X protocol more usable. Some of the libraries also provide client-side code which is not strictly part of the X protocol but which have traditionally been provided by Xlib. Renderutil module s Convenience functions for the Render extension. WWW: https://xcb.freedesktop.org/