It looks like they ginned them up from relevant specs they stuffed in and and the model’s latent knowledge of QEMU VirtIO and the absurd GPU-managed system architecture that is the Pi.

The models have seen several IP stacks before, plus many copies of the Linux, BSD, etc. source trees.

It’s not actually hard to write a network stack, just tedious.

Unfortunately, the talking horse’s OS hasn’t bothered with syscalls and lacks any notion of memory protection, and has a terrible userspace API which e.g. puts waiting for a ping response entirely in kernel.

 * Programs call kernel functions directly - no syscalls needed.
 * Win3.1 style!

Usually people don’t manage to produce an entire operating system without knowing why this is a bad idea.