It's really simple. Sometimes something you say will cause ChatGPT to make a one-line note in its "memory" - something like:

"Is an experienced Python programmer."

(I said to it "Remember that I am an experienced Python programmer")

These then get injected into the system prompt along with your custom instructions.

You can view those in settings and click "delete" to have it forget.

Here's what it's doing: https://chat.openai.com/share/bcd8ca0c-6c46-4b83-9e1b-dc688c...