One of the things that I really like about this post from Weirdbits is that it is also sort of a short course on what's in a humbucking pickup and how it works in the mechanical sense. It's interesting even if you never crack open a covered humbucker.
When I got my first kit, this post led me to an interesting discovery. The kit was a bass that came with a set of covered humbuckers that had flat tops with no screws. I assumed that it would have bar-magnet pole pieces like in a Thunderbird or Firebird humbucker. Instead what I discovered was that the pickup was actually a six-pole guitar humbucker. That led to swapping out the pickups...and after that a whole lot more modifications.