Are these graves/headstones Easter eggs for something?

https://preview.redd.it/0aa678or1zjg1.png?width=1920&format=png&auto=webp&s=9d8c5132c50aa2a4443b49dc1bc45641ee40a3c3

https://preview.redd.it/nx5balhs1zjg1.png?width=1920&format=png&auto=webp&s=277c0693a5653e46381811ffc66c4a647533310b

I was wandering around a dead server, and found them outside the map. They look like player usernames or something? They could just be random names, I'm just curious.

(Apologies about the quality)