Ask HN: Does anyone else also have a thick black line at the top of the screen?

Yes, it's an HN tradition to acknowledge the passing of notable figures in the community. On this particular occasion, the individual is Larry Tesler.

https://news.ycombinator.com/item?id=22361282

And/or Bert Sutherland.

https://news.ycombinator.com/item?id=22370667

And Peter Montgomery.

This has been a tough week losing more than one of our industry pioneers.

HN does that when somebody important to tech has died.

Yes. Looks like the culprit is:

I was about to ask the same. I assumed it is because of Larry Tesler's death.