This is odd to me, because surely they have to maintain that list anyway so they know which dependent packages need to be tested before releasing bugfixes? Or

This is odd to me, because surely they have to maintain that list anyway so they know which dependent packages need to be tested before releasing bugfixes? Or is that step just not happening? I just feel like, one of the big points of a package manager is that I can look up "what is program X's dependencies, and what packages rely on it?"