Currently, net.minecraftforge.eventbus.api.event.characteristic.EventCharacteristic is a sealed interface and only supports 4 types. These types are intentionally hard coded in the internals as they are used to determine how to handle the event bus when it is created with the relevant type. In a sense, it serves the same purpose as the Event interface, which itself is already in the net.minecraftforge.eventbus.internal package. Keeping the event characteristic base interface in the public API is confusing and could lead to unwanted assumptions about how characteristics are dealt with.

We're still in beta for EventBus 7, so I simply suggest that this interface be moved into the internal package so consumers cannot interact with it.