RTG

RTG or Random Terrain Generation is a feature introduced in the Test versions.

According to the creator, it has been made "so that players don't say where the ores are on the Internet".

PFTs
PFTs or Pre-Fabricated Terrains are a bunch of different world generations made by the creator. One of them is then chosen and built into the world using a Script. It gives the illusion that a Script builds the terrain automatically on start, but PFTs have been created manually.