MinecraftForge/MinecraftForge — pull request #292 by Chicken-Bones (2012-12-04 00:19:16+00:00)
Title: Added PreLoad world event for mods to initialize external data structures that require active worlds.

The need for this event arises from Forge and other mods loading chunks during the Load world event. This results in ChunkDataLoad events and methods like TileEntity.validate() being called before a mod gets its turn on the event queue and said external data structures may not be initialized yet.