I read the first few paragraphs. Very much reads like LLM slop to me...

E.g., "Zig takes a different path. It reveals complexity—and then gives you the tools to master it."

If we had a reliable oracle, I would happily bet a $K on significant LLM authorship.

Yeah and then why would they explicitly deny it? Maybe the AI was instructed not to reveal its origin. It's painful to enjoy this book if I know it's likely made by an LLM.