title: use of app file in products folder in xcode 5
body: <p>I wish to know the usage of .app file that comes in products folder while creating an xcode project for iOS. </p>
  
  <p>app file appears red when run in simulator, but appears when run in device.</p>
  
  <p>I right clicked on this file while running it in device. Now how can I use this app file?
  What is the use of this file? Please let me know.</p>