Yes! Apple used to have Technical Notes that were a deep dive into how the OS is implemented. They were super helpful in troubleshooting and optimizing for Mac OS. They haven't published anything like this in over a decade.
I suspect someone took "hiding implementation details" too seriously, and now Apple never talks about how anything works (it's all magic). You only get function's signature, and "documentation" that is basically just the function name with added spaces between words.
Why in the world is this a random undiscoverable post in the (terribly designed) developer discussion forums rather than a Technical Note in the documentation? It would have been a TN in the past. In fact that same engineer wrote a number of old Apple TNs.
It's clear even to some within Apple that there's a need for more and better documentation, but some pointy haired boss in upper management seems to think the current situation is fine.
It might even be in their interests to drive away all but the most dedicated developers. After all, they have more apps than they'll ever need, the problem is always quality.
When I worked at Apple in the mid 90's, DTS had to hire someone to go around to every engineering team to collect what they had change so we could write a tech overview of an OS release, otherwise no one would have known what changed. But then was when Apple was going out of business.
There are good reasons to hide the implementation details in documentation. The primary being it’s easier to keep the documentation up to date, our primary topic here. Many languages even publish class interfaces but not necessarily implementation details.
That said, a couple of example code snippets on using the interface wouldn’t hurt.
It’s always the null cases that get you... I suppose if “up to date” was the only requirement I would agree. But in reality there are many competing requirements which is why there are many degrees of documentation. Obviously internal and external documentation will be different too.
The reason to keep implementation details out of the docs is that people will rely on those implementation details, and then when their app breaks, they won't even think of looking at the documentation for updated implementation details. After all they probably have the old version all but memorized, and the app may break in a way that isn't obviously related to the implementation that changed.
I suspect someone took "hiding implementation details" too seriously, and now Apple never talks about how anything works (it's all magic). You only get function's signature, and "documentation" that is basically just the function name with added spaces between words.