Unity Framework folder that you have to add to Xcode for launching the app on iOS
When integrating the unity source code into the flutter application, one of the steps on https://github.com/juicycleff/flutter-unity-view-widget is: 6.5 Add the UnityFramework.framework file as a library to the Runner project.
Screenshot of Xcode settings: https://github.com/juicycleff/flutter-unity-view-widget/blob/master/files/libraries.png?raw=true