Was about to upgrade for the first time in a long while. Found that the downloads were, in fact, ZIP archives despite having no extension. The docs does say to unzip it, of course, but they also don’t seem to be all that up to date. Please add an extension!
Also, the docs mention the existence of Debian packages, which I believe is how I installed it last time, but the downloads page only has unstable packages. Not sure whether that is intended.