I agree, it'd be great if Apple provided accessible documentation in the first place. Time was, Apple published self-contained docsets that you could download and read offline.

Apple's ToS pretty explicitly forbid the kind of automation required to download everything. But even if someone did that, it'd only be a snapshot in time. And a lot can can change between OS releases.

As for the hosted web app, I wanted to provide this as a public service. I plan to open source it, so anyone can self-host instead, if they're inclined.