I was looking at the XNU source code today (don’t ask) and stumbled upon this line in a particular file (https://github.com/apple/darwin-xnu/blob/0a798f6738bc1db01281fc08ae024145e84df927/libsyscall/Libsyscall.xcconfig)
SUPPORTED_PLATFORMS = macosx iphoneos iphoneosnano tvos appletvos watchos bridgeos
I can tell you what all of those are including the new Bridge OS that powers the Arm chips on the new Macs. I have never heard of iPhoneOSNano before. There are several references to it as a supported platform if you search for it https://github.com/apple/darwin-xnu/search?utf8=✓&q=iphoneosnano&type=
Does anyone have any idea what this is?
/* Platform: iPhoneOSNano */#define __DARWIN_ONLY_64_BIT_INO_T 1#define __DARWIN_ONLY_UNIX_CONFORMANCE 1#define __DARWIN_ONLY_VERS_1050 1#endif /* PLATFORM_iPhoneOSNano */#ifdef PLATFORM_iPhoneNanoSimulator/* Platform: iPhoneNanoSimulator */#define __DARWIN_ONLY_64_BIT_INO_T 1#define __DARWIN_ONLY_UNIX_CONFORMANCE 1#define __DARWIN_ONLY_VERS_1050 1#endif /* PLATFORM_iPhoneNanoSimulator */
Update: Its been there since 2014. No idea what it is though
My guess is that it is a version of Darwin embedded into a few accessories, such as the lightning HDMI display connector.
That’s a good guess. Would explain the need for the simulator if third parties are going to test it.