Nice job. I also put together an HN-related Tampermonkey script a while back which adds an "Engaging" tab to the nav bar to show recent HN submissions with a minimum of 5 comments.

More stuff should be written using Tampermonkey. I see so many bespoke Chrome/Firefox extensions that could have just as easily been simple user scripts.

It also decreases the malware vector surface of malicious actors buying up extensions from many to one.

Consider publishing your script to the Greasy Fork site as well.

https://greasyfork.org