OK. I think they are unrecaptured 1231 losses. That is, in 2018 there were net 1231 losses. They get carried forward for 5 years to offset any 1231 gains (ie to make them get treated as ordinary gain and not capital gain) Where would you enter these if you had a new client?

Is there a carryover section?

Is there a spot in the Schedule D section?

I don't use ProSeries so I'm guessing.

8582 is the passive loss carryover form. These do not belong there.