This is killing me...
Looks like they've taken a step in the right direction. Still baffled how a company that prides itself on design has always catered very little to designers in terms of documentation and resources. They need to follow Google's lead and release something akin to the design.google.com
Apple has published guidelines since at least iOS 2, way before Google.
Also a few posts down currently: https://www.designernews.co/stories/70542--ios-human-interface-guidelines-updated-for-ios-10