Why did HN add a black strip on top?
Is this in acknowledgement of Kevin Mitnick's untimely passing?
Yes. It gets added when someone in the computing world passes.
> Occasionally, there will be a thin black bar at the top of the top bar, in memoriam of a significant figure in the tech/science community dying. A Hacker News submission about the death will usually be on the front page at that time.
https://github.com/minimaxir/hacker-news-undocumented