If you are encountering this keyword as part of an error message or a specific open-source repository, it is recommended to check the project's or INSTALL file for exact instructions on enabling optional multiplayer modules.
An "optional multiplayer build" configuration is a classic example of this methodology. It grants studios the flexibility to toggle entire networking blocks on or off based on the target deployment platform.
Build definition and configuration - PlayFab - Microsoft Learn
Compressed data blocks containing the baseline single-player game engine, logic, and base maps. fg-selective-english.bin
Open your official before starting the game. Ensure your friends are using the identical repack version and build number.