Steps:

  • obtain the app from App Store (just download it to mobile phone)
  • obtain Apple Configurator, this is Apple's application for managing iOS devices for business and schools
  • connect iPhone over cable and see it in the Apple Configurator
  • add app from your device in Apple Configurator
  • in terminal open Library/Caches/Assets/TemporaryItems
  • here you will be able to find .ipa file of your application

Time to inspect .ipa file:

  • rename it to .ipa.zip and uncompress zip archive

Have a fun!

What can we get/inspect: assets, libraries other resources related to the application. Good practice is to verify linking with static libraries that can be used in multiples places.