Not that familiar, but this is sid, which is where debian development happens. If there's a huge drop, it is most of the time because a package a lot of softwa

Not that familiar, but this is sid, which is where debian development happens. If there's a huge drop, it is most of the time because a package a lot of software depends on got updated or modified (e.g. built with different options) and it caused ABI changes, thus causing rebuilds of everything that depends on it.