From a perspective of iOS/macOS developer (who I am) the win-win situation would be if Apple incorporates those other bestest things like WebURL or improved json parsers into their frameworks so that even those people who have "no third party code" policy can benefit.
JSONEncoder/Decoder is an example of blurriness in the rules here... I don't foresee (or want!) Karl or John chasing up people here with "stop discussing JSONDecoder, it's Apple close source implementation!". And if discussions about NSURL or json alternatives are ok, I don't see how discussions from my hypothetical example above are not (e.g. something like this but less dead). Hope this is not an indication of UI-intolerance expressed by server oriented people of this list. Unless of course UI topics are prohibited by rules here, even if they are not discussions about Apple frameworks.. Let me double check... which brings me to the question: where are these rules written? I thought they would be pinned here in some code of conduct or FAQ or something but I don't see them.
Example of what's currently pinned:
If you haven't been here for a while you'll have no clue that topics about Xcode or SwiftUI / UIKit / Foundation are not appropriate here as they can be perceived by "related tools" by significant number of not so experienced iOS users (let's face it - iOS users are the majority of swift users as of now).