`Sorry, yes, I was talking about forum pages, not wiki.
I never noticed the M/N numbers in the lower right. So now I can see the replay number. How do I get that into a URL?
I want to link to the second reply in this discussion. By clicking “Replay as linked Topic” I discovered that the URL for a reply is the URL for the page followed by /N.
So that’s an answer. Is there an interface for this or do I just do it manually? Not that common, so manually not a problem.