For traditional Norwegian profiles, the consensus is to use the patronym as LNAB. If the patronym is unknown, one should use either a "farm name" or "Unknown".
Just now, I entered a profile for a woman whose patronym is unknown, and I found it inappropriate to use the toponym "Haugen". But after orphaning her, I find that the "Unknown" LNAB is replaced by "[family name unknown]" which is even more inappropriate. "Family names" were largely a foreign concept in Norwegian culture until late nineteenth century.
For patronymic cultures, I find "Last name" to be more culture neutral than "Family name", and "Last name" is what is being used everywhere else in WikiTree. So why does the "Family name" pop up here?