I can say with full certainty that thousands of engineers at Google were feeding their day to day LLM assisted coding queries in to the ChatGPT web ui for about

I can say with full certainty that thousands of engineers at Google were feeding their day to day LLM assisted coding queries in to the ChatGPT web ui for about 2 years before a custom Chrome extension was pushed to employee laptops to stop it. So GPT has likely post-trained on a lot of Google code knowledge.