There are 2 chocolate buildings in the game files. The developer abandoned these buildings because they didn't know what they should add to the game.
In order from left to right: The Cacao Farm, The Cacao Farm with a door, The Cacao Farm with growing trees
Cacao Farm[]
Cacao is grown here. It can be used directly as food or to make chocolate. Costs 20 Wood and 5 Stone. 500 knowledge to unlock.
Chocolate Factory[]
The Chocolate Factory in action
This factory uses cacao to make chocolate. Costs 30 Wood, 20 Stone and 150 Machine Parts. 600 knowledge to unlock.