Actually \ is AltGr++, i.e. "+" is the symbol you get from that key without any modifier. With shift you get ? and with AltGr you get \. My bad, and too late to

Actually \ is AltGr++, i.e. "+" is the symbol you get from that key without any modifier. With shift you get ? and with AltGr you get \. My bad, and too late to edit.