The X Keyboard (XKB) Extension essentially replaces the core protocol definition of a keyboard. The extension makes it possible to specify clearly and explicitly most aspects of keyboard behaviour on a per-key basis, and to track more closely the logical and physical state of a keyboard. It also includes a number of keyboard controls designed to make keyboards more accessible to people with physical impairments.

xkbcomp is used to compile XKB keyboard description files into formats usable by the server or client libraries.