I found it by going to Super Search and entering 'CPAN' for title text, then scrolled down to almost the bottom to click "Don't include Replies". and clicked "Search". That got me a list of root nodes with "CPAN" in the title. At that point, I just scanned down the list until I saw what I was looking for. I had the advantage of knowing it was there and the disadvantage of forgetting how long ago it was (I had to look back farther than I thought).