More like dupe detector buster - the link has been submitted some 4 months ago[0]; adding ?hn is a semi-conventional way to get it to appear as a new submission instead of counting as an upvote towards the older story.

--

[0] - https://news.ycombinator.com/item?id=40921398

Self-promotion within reasonable limits is perfectly fine on HN.

It is, but notice that every one of this person’s posts is self-promotion and they hardly interact with HN otherwise.

Edit: You have to turn on showdead to see most of their posts.

Yeah, absolutely! Just thought it would have to be tagged as such somehow?