Why do twix cookie bars have holes in them?

The holes in Twix Cookie Bars are not intentional and are a result of the manufacturing process.

The bars are made by pressing cookie dough into a mold and baking it. The holes form when the dough expands during baking and pushes against the mold. This is a common occurrence in baking, especially when using a high proportion of baking powder or soda.

The holes themselves don't affect the taste or texture of the bars, and they are considered an acceptable variation in the manufacturing process.