Alternatively, we handle those mappings ourselves so you can change the default in FPS4Misc::GetDefaultLocale. I don’t know how we ended up using “no” as it’s not even a valid culture code… I’ll fix that.
Edit: Weirdly ICU has “no.res” and “nb.res”, but no “nn.res”… curious.
It looks like ICU itself lets you select and use “no” as a culture if you do it manually, but the call to getAvailableLocales in ICU doesn’t include it (which is why you can use it, but not select it as a language in the localization dashboard).