As far as I could tell, the book didn't match what's posted online today. The text was somewhat consistent on a topic, yet poorly written and made references to sections that I don't think existed. No amount of prompting could locate them. I'm not convinced the material presented to me was actually the book, although it seemed consistent with the topic of the chapter.
I tried to ascertain when the book had been scraped, yet couldn't find a match in Archive.org or in the book's git repo.
Eventually I gave up and just continued reading the PDF.