It didn't appear in Show HN at all. Perhaps because another user posted it as a regular topic just a few minutes earlier, which drops off very quickly (within minutes) - but I think the issue is wider.
For a while now, I've felt that the new topics stream requires you to promote the topic outside of HN to be seen on HN - sometimes by adding a "Discuss on HN" link in the blog, or on social networks etc. The problem is quite fundamental: the "Show" link gets a small fraction of clicks. The "Show New" (two clicks away) probably gets tinier, miniscule fraction of clicks. The intersection of people who are interested in the project and those who have clicked "Show New" would be very nearly null. So upvotes will have to come from outside.
I've moved the URL out of the link at the top, which seems to be helping for now.
(now I have to decide whether to go down another rabbit hole and fix that)