Intelligence isn’t "implemented" in an LLM at all. The model doesn’t carry a reasoning engine or a mental model of the world. It generates tokens by mathematically matching patterns: each new token is chosen to best fit the statistical patterns it learned from its training data and the immediate context you give it. In effect, it’s producing a compressed, context-aware summary of the most relevant pieces of its training data, one token at a time.
The training data is where the intelligence happened, and that's because it was generated by human brains.