packages/flutter_tools/templates/create/ios-objc.tmpl/Runner/main.m

#import <UIKit/UIKit.h>
#import <Flutter/Flutter.h>
#import "AppDelegate.h"

int main(int argc, char * argv[]) {
  @autoreleasepool {
    return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
  }
}