ABC header for Norwegian

Can you remember how I set up a template for this (sometime last year I think), adapting it from Danish? I now have Teodor605 asking me how to do it, as I mentioned the lack of one in Norsk Wiktionary. I can't find the discussion we had, in the Grease Pit I think.

What's an ABC header?

Like here (an index I suppose) - Aa, Bb, Cc etc. https://en.wiktionary.org/wiki/Category:Norwegian_Bokm%C3%A5l_nouns. I can't find the template.

It's at Template:nb-categoryTOC.

Ah, thanks for finding it. I was looking under index templates. I will send it to Teodor.