There’s a world of difference between can and wants to. And as I already pointed out, the existing client is incomplete in important ways, like error handling. So even if I was excited to fuck around figuring out how it works, it still wouldn’t be as good as actual documentation.

I get that this isn’t important to you, but continuing to insist that it’s documented when it objectively isn’t is indefensible. Just say that you don’t care and let folks decide whether they want to deal with it or walk.