This is the very last scene in Mass Effect 3. Shepard is, together with the catalyst, at the top of the citadel. He can choose 3 possible solutions, which will show 3 different final cut scenes – or not 😀
Well, if you finished the game and are somewhat disappointed by the game series finale you might wonder if another option would have provided a more satisfying ending. With this save game you can!
At this point you cannot save the game, hence the autosave. The file will be overwritten once you make one of the 3 choices, if you want to see the other 2 ends you need to recopy the autosave.
The 3 options are to control the Reapers (left), merge machine and organic lifeforms (middle) and destroy all artificial life (right).
In case you missed those before, after the credits there are some bonus scenes, far in the future.