Well, to get one you need to be in the main menu, then go to load game and at the bottom right press To File
To find it, just press upload file and then search for a "save1234567890.mdrg" or "saved-on-(date and time).mdrg" in the files if your doing the save editor
Its either one of those two names, so if you reset your browser or smth, you can just load that file you had saved. Like a backup.