OP here. I think it's a bit reductive to think that GPT simply copy pastes. It sometimes does. But my experience working with it nearly daily since December, is that it's also quite capable at reasoning. My sense is it most likely saw the API endpoint in another context, learned how it was parsed, and then adapted it to my situation. Perhaps it even parsed the documentation page itself.

If the code has been done hundreds or even thousands of times, what meaningful attribution could possibly be added? Like, we don’t add attribution to each for loop even though it’s not our original idea.