Why do you think it isn’t due to the programming by example work that MSR have been doing for over 5 years and which already partly made it into excel as flash fill?
You're right, "almost certainly" is far too strong. I was unaware of that research, and read a lot into that this is only being released in the web version. And am just generally anticipating a wave of LLM applications to eat everything that could be even remotely, abstractly reframed as an "autocomplete" task. That it only works in English is also evidence against, with GPT-3 you'd get every language it knows pretty much for free.