The other day I jumped into a forest mine and instead of seeing a banner that said "forest mine", the banner simply said "Ray". Whenever anyone entered, the system message would say "[player name] has entered Ray." I thought this was pretty funny. I am guessing it is some kind of inside joke among the developers. By the way, this was not a player realm with a stamp on it. This was one of the actual forest mines. I may need to explore all the mines in all the worlds to see if there are more things like this. If you're interested in looking for it, i think it was on Spyre.