This simple Fabric mod sets the online-mode value to false for the integrated server, so one is able to join a LAN world using a Mojang account.
This is already possible with dedicated servers, and you still need an official account to start the game client, therefore this mod doesn't enable any form of piracy.
This mod works on versions 1.19 - 1.19.2 and most likely future versions.
This is a Fabric mod, so you'll need to install Fabric and the Fabric API mod before installing this mod.