Where did you see the 260 cM match? DDP only shows Passmarble with a match of 7.7cM.No name for the match unfortunately. The DDP stoped updating their spreadsheet, so I don’t know if he has any other highest match. But I think you can send a message to the DDP, it might be helpful.
I've been searching the GedComs for the possible last names that have kits associated to see if I can find Passmarble and start from there. Of course, this is like finding a needle in a haystack.