Yeah on macos the communication between your app and the window server (which is conveniently called WindowServer) happens via mach ports. Most of it is undocum

Yeah on macos the communication between your app and the window server (which is conveniently called WindowServer) happens via mach ports. Most of it is undocumented, in fact anything more "low-level" than using AppKit is undocumented, although IIRC it is in principle possible to use undocumented CG* apis to create and manipulate windows yourself without going through the appkit layers. I think each CG* api is basically a thin shim that communicates to the window server, which has a corresponding CGX* implementation which does the actual logic. This article has some details https://keenlab.tencent.com/en/2016/07/22/WindowServer-The-privilege-chameleon-on-macOS-Part-1/ https://keenlab.tencent.com/en/2016/07/22/WindowServer-The-p...