I was using a custom keyboard layout. Basically I modified the us-mac layout to fit my ideal of a math-heavy version of the regular us layout that also throws German umlauts into mix. It went well and worked marvelously for 6 consecutive versions of Ubuntu. Today's version Upgrade (from 13.04 to 13.10) broke that streak. I now have the usual crappy Macintosh-Layout.
Now xkb just ignores my layout and all of the other changes I make in
/usr/share/X11/xkb/symbols/us (tried to switch '0' and '9' everywhere and rebooted – no effect). Why is that?
I suspect I have to do an extra step now for the changes to take effect or something like that. Anyone care to point me in the right direction?