The leak, which was posted by GTA 6 News on X, shows more than just the screenshot. It also shows pictures of a PS5 dev kit unit, which seems to be what the game is being tested on during development.

Ex-Rockstar Dev on Why GTA 6 Will Skip a PC Launch at First With GTA 5, York commented that Rockstar made the PS3 a priority, and worked on the Xbox 360 port at the same time.