X Keymap

X Keymap (.xkm) is a binary file format to map keyboard keys to input characters and actions used by the X Window System.

When the X server needs to load a given XKB keyboard layout description, it runs the xkbcomp command to compile the plain-text description files (usually the ones maintained by the xkb-config project) into the .xkm binary format, which the X server then reads using the API provided by libxkbfile.

Specs

 * Specs as .h files

Software

 * xkbcomp: git repo, tarball releases
 * libxkbfile: git repo, tarball releases

Resources

 * XKB - X Keyboard Extension
 * Wikipedia: X keyboard extension