Wedge

Now here is the list of hooks categorised by hook. As you can see in the bottom category, test_hook, which is an arbitrary hook, no remove box appears. The chance of this changing is quite small, even though it's a glitch.

Here's the (mostly) current state of play of the add-on manager.

I have altered it very slightly since this picture was taken, namely that the enable buttons actually line up now, as opposed to being misaligned as they are in this picture, but that's not really a big deal.