Minecraft wiki entry for Development_versions, associated text: Renamed World.event.weatherChanged to World.event.changeWeather
Added event World.event.addEffect
Fires when an effect is applied to an entity.
Added event World.event.createEntity
Fires when an entity is added to the world.
Removed function World.addEventListener
Changed function getDuration() to property duration
Changed function getAmplifier() to property amplifier
Added property displayName
Gets the display name of the effect