> But then how are other people posting screenshots of it?
This community have some authors of Mario makers.
Mario maker screenshots are posted by Each of authors.
@D.J.
It seems there are rules in the Japanese SB community that PROHIBIT users from posting keys in which unauthorized copyright characters (like Mario) have been used. They can still share screenshots but such keys will be deleted from their server. For this reason Tsubasa was trying to tell you not to inquire further. Nekohachi's XKSKQPJX is probably the closest thing we can get.