Ask HN: What's the black bar at the top of HN?

I've noticed this bar above the orange header of HN, but it's only there about once a month or so (maybe less?).

It seems to contain an image (s.gif, served from this domain), is it some sort of local analytics tracker?

  • Today, it's for Joe Armstong ( author of Erlang and computer scientist ).

    https://ferd.ca/goodbye-joe.html

    Sort of like a black armband, for the website.

  • It's there when an eminent person in the field has died, for about a day.

  • It would be nice if the bar could link to the main discussion thread or a page with a short description.