That post is from 2014. He released it in 2017:

https://fabiensanglard.net/gebb/ https://fabiensanglard.net/about/index.html

It came out in 2017 https://www.amazon.com/Game-Engine-Black-Book-Wolfenstein/dp... as per the bottom of https://fabiensanglard.net/about/index.html

https://fabiensanglard.net/about/ has all of them at the bottom - there is one for Wolf3D and one for Doom - highly recommended.

The CP-System is also interesting, even for someone like me who never used one. But not quite as interesting (to me) as the other two.