We failed to find the hidden information on the server, here are the filles.
Flag format: CTF{xxxxxxxxxxxxxxxxxx_xxx}
CTF{this_was_a_hidden_room_lol}
Search the map database to find all signs and their text
We get a bunch of files for a game called minetest, and we have to find a secret, somewhere. The first thing I tried to do was downloading the game (using brew) and running the world with a player called Splasher (found in the logs file).
We spawned on top of a sign, saying Try harder. To find the flag, we thought that we had to search for all of the signs in the map and read them all.
We generated a top view of the map, which didn’t help much:

We then started going through the world files and found map.sqlite, which, according to the minetest documentation, contains information about the blocks (nodes of 16x16x16) that have been generated.
We opened it up and we found pos and data for all blocks:
