LANBeacon

When you run a vanilla dedicated Minecraft server (e.g., server.jar), it does not broadcast its presence over the local network. In Minecraft, the “Open to LAN” feature is triggered by the client: when a player opens their single‑player world to LAN, the client starts sending a special UDP broadcast packet. Other clients on the same network see this packet and display the world in their multiplayer LAN list.
A dedicated server, by default, only listens for incoming connections; it never announces itself. As a result, even if you are on the same local network, launchers like HMCL, PCL2, or the official client cannot discover your server via the LAN scan.
This mod mimics the behaviour of a Minecraft client. Once the server has started, it periodically sends the exact same UDP broadcast packet that a client would send when opening a world to LAN. The packet contains the server’s MOTD and port number.
When any Minecraft client (or launcher with LAN scanning) on the same network receives this packet, your server automatically appears in the LAN server list. Players can join directly without manually typing an IP address.
So it can also allow multiplayer software like terracotta to detect your server processes
(开发过程中使用了 DeepSeek AI 辅助编码)