The Guantanamo Bay files leak is when a large group of secret documents were released that were secretly recorded by people in the US government about the people they held at Gitmo. This meant that the public could learn what the US was doing at the prison there, like how they were treating the prisoners. It also included descriptions of how top government officials were running the operation. The documents showed how some of the detainees were treated harshly and why some of them were detained for years without trial. This created a lot of debate and controversy over what was happening at Guantanamo Bay, and it led to the US government changing some of its detention policies.