An event bus is a specific context in which events will occur. Any events sent along them will be handled by event handlers that exist within the context they are sent on.
In SurvivEngine, there are 2 forms of event bus in use:
The game event bus is responsible for sending game events that need to be handled by large game systems or will have effects that impact the entire game.
An entity event bus, belonging to a specific entity, will send and receive events that should be handled by listeners on the entity it belongs to. This event bus is more focused and localized.