Boss Event Settings hold flags relating to the boss bar used by Gateways. Every field on this object is optional, meaning that {} is a legal definition of a Boss Event Settings object.
{
"mode": "string", // [Optional] || The drawing mode of the boss bar. Either "boss_bar" or "name_plate". Default value = "boss_bar".
"fog": boolean // [Optional] || If the current mode is "boss_bar", this controls if fog is enabled. Has no effect when the mode is "name_plate". Default value = true.
}