The fancy security properties they’re talking about rely on a whole lot of closed source code not included there. Though an Apple intern did “donate” some of it to the public years ago.

Why the ever-living fuck do you think I should take Apple's documentation seriously when they lied through their teeth about the Push Notification architecture?

This isn't source code, it's marketing.

It's a link to source code on GitHub. It could be marketing too, but it's absolutely, incontrovertibly source code.