That mysterious BioShock Collection for the PC, Xbox One and PlayStation 4 may be one step closer to its official announcement. The three game bundle of BioShock, BioShock 2 and BioShock Infinite for current generation game consoles has now been rated "M" by the Entertainment Software Ratings Board in the U.S.

The game was first leaked in September, via a listing on a South African game retailer, and since then it has been listed by the game ratings boards in Taiwan and Brazil. The U.S. ESRB listing would seem to confirm the BioShock Collection is real, but the franchise's publisher 2K Games has still not officially announced the bundle. There's also no word on what graphical changes, if any, have been added to the three games.

The original BioShock was released in 2007 by Irrational Games, and was highly acclaimed for its narrative of an underwater society that has suffered a disaster. The sequel, BioShock 2, was developed by 2K Marin and released in 2010. BioShock Infinite, which switches the setting to a floating city in the sky many decades before the first BioShock game, was released in 2013 by Irrational Games.