If the readme is anything to go by, this doesn't look like it was written by hand. Codex if I were to guess. I wonder the coding agent "improved" the code.

The readme hints at the prompt:

> It keeps the original system's semantics — what it does — while rethinking how it's expressed: stronger types, clearer module boundaries, idiomatic abstractions everywhere.

"idiomatic abstractions" would certainly bloat the line count.