As you may know, you can save your App Inventor project to your local computer using the Projects | Export selected project (.aia) to my computer menu option:
Use this feature to save a backup copy on your local computer or to share your code with others (email or transfer the file using DropBox – or similar – or merely copy to a USB thumb drive).
What is inside the .aia file?
Surprisingly, the .aia file is just a regular .zip file. You can verify by saving a copy to your local disk drive, and then rename the file to have a .zip file extension instead of .aia. Then use Windows Explorer, StuffIt Expander or other utility to open and decompress the .zip file.
PLEASE NOTE – DO NOT MODIFY THE CONTENT OF THESE FILES. THIS INFORMATION IS NOT SOMETHING YOU NEED TO KNOW TO WRITE APP INVENTOR APPS AND IS PROVIDED “AS IS” “FOR YOUR INFORMATION” ONLY.