In OpenAI Pro ($20/mo) one can start a project with a set of files. Various chats can be had about this project topic with the files providing additional information. I've discovered the projects are isolated. They'll use memory configurable in settings but they don't use chat history outside the project. This can give ChatGPT chats in projects a different tone.

My question is this: Is this fine tuning with those project documents or RAG and what's the difference?