When a save is deleted, and you click on it before it disappears, you will see this mysterious save made by user FourOhFour and says it was uploaded in 1970. The unknown user doesnt seem to exist when i search him up. Weird. I can't screenshot so ill just give you an image that looks exactly like the save.
it's a placeholder save with id:404, basically if the server has no data to read or if it suspects you of scraping(i think) it shows this instead. you cant comment on it either so thats weird
i don't do tpt coding and am a normal user but im pretty sure this is what it is
Also FourOhFour is an actual user, but his only save, Id:404, is unpublished, making it not appear in the save browser.
FourOhFour = 404
id:404 = 404
404 = Can't find this thing
1970 = some default time