Apple's TestFlight is a service that developers can use to test when releasing iOS applications. It was recently discovered that it can be archived through Wayback Machine (time machine) and then shared anonymously on Twitter. The leaked content includes applications published through TestFlight, as well as game prototypes and beta files, including several "Angry Birds" games that have not been released on the App Store.

However, the source of the data in this leak, known as "teraleak", is not yet clear. Judging from the exposed data, it includes old applications and game programs that ran on Apple's TestFlight service from 2012 to 2015, with a capacity of up to 1.2TB, and approximately tens of thousands of iOS applications and games.