@quanl222 (View Post)
In-game, right-click on a save from the save browser and click "View History"
Either that, or type "history:123123" in the search bar in the save browser in-game or here on the website to view that save's history (in my example, that would be save ID:123123)

Here is an example of it being done on the top save on the FP right now: https://powdertoy.co.uk/Browse.html?Search_Query=history%3A2579923
Notice what is written in the search bar