Structure of the IPA

An IPA has a built-in structure for iTunes and AppStore to recognize, The example below shows the structure of an IPA,

/Payload/
/Payload/Application.app
/iTunesArtwork
/iTunesMetadata.plist

As shown above, the Payload folder is what contains all the app data. The iTunes Artwork file is a 512×512 pixel PNG image, containing the app's icon for showing in iTunes and the App Store app on the iPad. The iTunesMetadata.plist contains various bits of information, ranging from the developer's name and ID (e.g., Google), the bundle identifier, copyright information, genre, the name of the app, release date, purchase date, etc.