Minetest (server) is a near-infinite-world block sandbox game and a game engine, inspired by InfiniMiner, Minecraft, and the like.
You can find the world maps, mods folder and config files in /config/.minetest.
If you want to override the advertised port, ensure you add --port in your CLI_ARGS AND ensure the internal port reflects the change, ie; if you set your advertised port to 40000 with --port 40000 then your ports declaration should be 40000:40000/udp