The engine’s C and C++ code are compiled with LLVM. The Dart code (both the SDK’s and yours) are ahead-of-time (AOT) compiled into a native, ARM library. That library is included in a “runner” iOS project, and the whole thing is built into an
.ipa. When launched, the app loads the Flutter library. Any rendering, input or event handling, and so on, are delegated to the compiled Flutter and app code. This is similar to the way many game engines work.
If you like this question & answer and want to contribute, then write your question & answer and email to freewebmentor[@]gmail.com. Your question and answer will appear on FreeWebMentor.com and help other developers.