There is a bug largely detailed at https://bugs.launchpad.net/ubuntu/+source/linux/+bug/214786: on ISO Apple USB aluminium keyboard, the key right to the left shift key, which is usually not a letter on keyboard layouts using this physical layout (one more key on this row as compared with US) is swapped with the leftmost key on the numeric row.
So far, the only solution seems to be what is in https://help.ubuntu.com/community/AppleKeyboard in "Correcting swapped keys and wrong keymaps for international (non-US) keyboards".
This solution was confirmed to work by several people (including me) but it would be more user-friendly to have an option in the GUI e.g. "Fix swapped key in ISO Apple USB aluminium keyboard" which fixes that.
EDIT: I forgot to mention that I am running Trisquel, based on Ubuntu, and which has MATE as default desktop environment.
There is a bug largely detailed at https://bugs.launchpad.net/ubuntu/+source/linux/+bug/214786: on ISO Apple USB aluminium keyboard, the key right to the left shift key, which is usually not a letter on keyboard layouts using this physical layout (one more key on this row as compared with US) is swapped with the leftmost key on the numeric row.
So far, the only solution seems to be what is in https://help.ubuntu.com/community/AppleKeyboard in "Correcting swapped keys and wrong keymaps for international (non-US) keyboards".
This solution was confirmed to work by several people (including me) but it would be more user-friendly to have an option in the GUI e.g. "Fix swapped key in ISO Apple USB aluminium keyboard" which fixes that.
EDIT: I forgot to mention that I am running Trisquel, based on Ubuntu, and which has MATE as default desktop environment.