The xkb file goes in /usr/share/X11/xkb/symbols/ (Maybe an entry also has to be added to /usr/share/X11/xkb/symbols/evdev.xml?) Reapply the Layout: Use `setxkbmap` to apply your layout again with `setxkbmap thomas`. Clear Cache: Ubuntu caches the keyboard layout data. If your changes aren't being recognized, it may help to clear this cache using the following commands: ```bash sudo rm -rf /var/lib/xkb/* sudo dpkg-reconfigure xkb-data ``` To check the current layout, you can use the following command: ```bash setxkbmap -print -verbose 10 ``` You can also use `onboard` to show the current layout on the screen.