The "ScratchCard_FREE.aia" file is a project export for MIT App Inventor containing source code and assets, designed for creating interactive scratch-off apps using Canvas or specialized extensions. It is imported into the App Inventor platform to review or modify its block-based logic, including scratch mechanisms and win/loss conditions. For more details, visit MIT App Inventor community forum . About .aia files - Google Groups App Inventor Open Source Development. Conversations. About. Google Groups [FREE] Scratch Off Extension for App Inventor