You know, an awful lot of these books are written by people who are interested in learning something, so they decide to write a book. They learn about the topic at the same time they write the book. It can lead to "interesting errors" in the book.
Sounds like this might be a way of trying to do that without creating the "interesting errors"...
![grin :-D](https://www.theswamp.org/Smileys/black/grin.gif)