I like to tweak my Colemak layout a bit, so I changed /usr/share/X11/xkb/symbols/us to contain my changes. Sure, they get lost on an upgrade, but that is not very often. After upgrading to 13.10, this does not work anymore. I changed the file, but the changes are not applied. Neither when I use the settings program, nor when I issue setxkbmap 'us(colemak)' directly. Where is this data stored now, is there some kind of cache?