.BO3 File Extension
What is a BO3 file?
Minecraft BO3 object file used by TerrainControl, a Minecraft modding application used to generate worlds; contains Minecraft terrain objects; also stores settings that control when sunlight, darkness, water, and lava are spawned in the world.
Minecraft objects consist of blocks that can spawn in your biomes. They can be ores, trees, dungeons, and other structures.
You must place the BO3 file in one of your two custom biome object (BOB) folders. The global folder allows all your TerrainControl worlds use the BO3 file. The local folder only allows one world to use the BO3 file.
BO3 stands for Biome Object Builder version 3. The BO3 format replaced the .BO2 format.