If you're talking about the German layout and AltGr, then so are the []{} keys, which are already used quite a lot in PHP programming.
It's the main reason why, even though my phyiscal keys are in German layout, I still have the USA layout in software. It's just nice to be able to make [] with a single key press :)
Not only that, it's very unconfortable to type in some international keyboard layouts.