Is there any way to extend the list of languages you can localise a
package to?

I was just playing around and tried to add Norwegian localisation to a
package I created, but just got a "no files were found" message every
time I tried to import the localised property file.

I tried several Norwegian locales (_no, _nb_no, nn_no and no_no) without

Is this a case of only the handful of languages that are presented
greyed out in the package properties pane are supported?

I renamed one of the localisations to _es and it was imported without a