QUESTION: `restore-chat-history` option

Hello! Thank you for the amazing tool!

I want to understand what exactly the `restore-chat-history` CLI flag does in aider. I have tried enabling and disabling it, but I do not see any difference in the display other than an extra message "Restored previous conversation history." on startup.

What is the intended design for this option? What does it do? Can anyone please explain in detail?