Having something Turing-complete is surprisingly easy, and it hides everywhere. The repository have a small document that explains how you can use printf() as a computer : it can performs additions, logical union and negation, which is enough.
It was unintentional, but Ken Thompson being Ken Thompson, can't be 100% sure.
Don't look at the end destination, look at the journey to the destination
* Learn low-level details of a basic but real-world CPU
* Practice the brain gymnastic of programming an atypical Turing-complete computer
Your created new connections in your brain, put to use some of the old established connections. Having a machine spit-out the emulator would rob you of all that. Like, you can drive from A to B, but running for A to B can do you much good.