From the install instructions on the wiki I remain with the impression that it will overwrite the standard layout (and it will be no longer accessible through shortcut), rather tahn just add one more layout. on the other hand this should be possible to be dome with other layout than 'us' (or not?).

And some few more questions - when I use more keyboard layouts (like non Latin ones), what should I put in the XkbSymbols for them - empty entry with comma, like the one for XkbVariant? And does XkbSymbols conflict in some way with XkbVariant? (Particularly, I use a 'phonetic' layout for Bulgarian).