alt Hacker NewsOff-topic, but it looks like the author is using the URL to determine how much traffic reached his article through Hacker News. The URL ends with "-hn", but if you remove that, it still goes to the same article (and links to the article from the same site don't include the "-hn").
Nothing wrong with it; I just thought it was interesting.
Author here--thanks for reading. I typically write several essays each day, which I send out in a newsletter and post on the website. I built a workflow to expose one of the essays separately for HN without any paywall or subscription prompt.
It's not as natural to submit a link to HN with three different essays that might all be relevant to this audience.