1. Locate the ipa file.
In Mac OS, it is located in
2. Rename the extension.
2.1 Right click on the package you want to open and select "Rename". In Mac OS, just press "enter"
2.2 Remove the ".ipa" extension and write ".zip" instead.
It will appear as a zip file
3. Open it as an normal zip file
Once it is opened, you can see the content. Normally, it contains tree files
- iTuneArtWork: an Binary file
- iTunesMetaData.plist: a XML file which contains the metadata information about the application: Its name, the AppleId, etc.
- Payload: It contains the application. It is just a directory, so you should be able to open it as normal directory.