Earlier quoted context omitted.
Android is only about Java. The NDK APIs are quite constrained and only meant to be used for Java native methods, real time audio and high performance graphics. Google can replace the kernel for anything else POSIX like, with the same set of NDK APIs. Since Android 7, they have been locking down access to anything else not part of the official NDK APIs.
That depends if you're talking about user docs or developer docs. I'm saying that we should document wpa_supplicant as user documentation: if there are caveats like, oh, "Android 5.1 and lower can't connect to TLSv1.2-only PEAP or EAP-TLS networks," that should be documented for end users but is irrelevant for devs since wpa_supplicant isn't accessible to the application at all. It's not a library/API, it's a system…
As for user documentation, any OEM is free to do whatever they feel like, so you don't have any guarantee how much of it is actually like AOSP.
Samsung is well known among Android devs for breaking AOSP compatibility.