Razing of Gallifrey

The planet Gallifrey was razed to the ground by. (TV: Spyfall)

Background
Despite living as and the Lumiat, lives where they had sought to do good in the universe, (AUDIO: The Lumiat)  returned to his dark ways. (TV: The Timeless Children) Though the Twelfth Doctor observed that Gallifrey, having been relocated to a pocket universe at the end of the Last Great Time War, had returned to the Doctor's universe at the end of the universe, (TV: Hell Bent) the Master claimed to the Thirteenth Doctor that Gallifrey was still hiding in its "little bubble universe" when he returned to it. (TV: Spyfall)

Aftermath
During the Kasaavin invasion of the universe, the Master made the Thirteenth Doctor aware that "someone" had destroyed Gallifrey. After visited Gallifrey and saw the planet in ruins, the Doctor found a holographic message from the Master in the TARDIS in which he admitted responsibility. (TV: Spyfall)