What does the symbol “~$$$~” in the file name mean?
Supposed you create a new scene, and assign the mrs file with the name 01.mrs, then close this file. Next time, you open it again, and do some modification to it, then save the file. Now, there will be two mrs files. The one with the name 01.mrs is the latest one, and it contains the latest information of the scene. And the 01.mrs~$$$~ is the one containing information when you save the scene at the first time. That means, you can go back to the stage before you do the second modification, in other words, the file with “~$$$~” is a backup file for the previous scene.