Copilot uses "OpenAI’s Codex model, a descendent of GPT-3".
Soon to be GPT-4, though.
How is this possible? They don't even use the same tokens, right? Whitespace is different IIRC.
I think the GPT-3 thing is wrong, but it is not impossible. You can always train an existing neural net to do new things right? Not sure how to handle different whitespace tokens.