This dictates whether the component will instantiate and spawn the objects as soon as the server starts, or only after you manually call Spawn on the ServerSpawner component.
You can disable this if you want to manually control when these objects are spawned.
This is a list of the Network Objects the component will instantiate once the server starts. The order of this list is respected when instantiating the objects, and the component will attempt to use FishNet's object pooling for the objects if they are added to the an object pool.