WorldHardcoreToggle toggles the 'hardcore' setting in a world's level.dat file. This resolves an issue where a world was generated with hardcore enabled in the server.properties, but now the owner no longer wants hardcore enabled in the world.
WHT was initially supposed to toggle and save the setting in the level.dat file, but the server would overwrite our changes on shutdown. So you'll need to manually rename the level.dat yourself.