• Swap control and caps lock
• Swap “ and @

Keyboard maps in X are configured in /etc/X11/xkb. Each locale has a single file in /etc/X11/xkb/symbols which contains details of all variants for that locale (often an international version with deadkeys and a dvorak variant). They're defined relative to some other layout (ie “start with the standard US keyboard then make the following changes…”).

Here is a version of the gb layout that includes a “hybrid” variant that swaps ” and @ back to their US positions (to overwrite /etc/X11/xkb/rules/gb – the extension needs to be deleted first). Then various config files need to be updated in order to be able to select this variant through the standard KDE system settings. These need to be overwritten in /etc/X11/xkb/rules:

• base.lst
• base.xml
• evdev.lst
• evdev.xml