I've referred to this for years as "ritual-taboo programming". Ritual-taboo societies are ones in which things are done in certain ways because they worked in the past, but no one knows why. Too much of programming is like that.

If you work from the specifications for a library, you'll probably find that some of the documented features don't work. If they weren't used by some "framework", or mentioned in a how-to book, they probably haven't been exercised well.