In scandinavian (sweden, finland) there is also different physical keyboard which has öäåÖÄÅ on the right side of the qwerty-keyboard - and especially up and down cursor arrows are behind alt-key, which makes Fennec zoom in+out (ctrl+up/down) keyboard shortcuts unusable.
(therefor I´ve suggested ctrl+I/O would be zoom in/out shortcuts in every GUI-program)