> perhaps this is all sanctioned

In short, it is not.

I received early draft from bas. While I encouraged him to finish his book, I also told him, in no uncertain terms, that I had released the source code to inspire people and give them a kickstart, but not for them to copy the content.

As months passed, I asked repeatedly to remove whole paragraphs he had copy/pasted as is, and drawings he had also copy/pasted. Later, as A.I became more powerful, I used it to compare Wolfenstein 3D and Keen book and noticed a lot more that was verbatim. At which point I told him I no longer wanted to help him in his project.

It is cool that someone documented Keen thanks to my framework. But I have only myself to blame for opensourcing the code of my books/website and thinking people would use it as intended.

PS: I commented it was a "good idea" to change the cover because originally this was going to be the "Game Engine Black Book: Commander Keen". I did not like that his work could have been mistaken for mine (he also elected to use the same style as my website for his website which only adds to the confusion).