This special page w:no:Spesial:Sporingskategoriar has a Nynorsk name. In Bokmål this should be “Sporingskategorier”, that is “er” and not “ar”.
I'm not sure where the names for special pages are localized. Once upon a time there was a special page for renaming of special pages, but it was so special that it wasn't listed as a special page…