What was the editor mentioned when OpenAI's Canvas was introduced?

Hi, I remember that when OpenAI introduced Canvas, someone in the HN comments mentioned another editor that did pretty much the same things—or maybe even inspired Canvas (I don't recall if it was an explicit influence or just a similarity pointed out by users).

I've tried searching through the comments, but as often happens on HN, it's a bit like going down a rabbit hole , and I can't seem to find that reference again. Unfortunately, I also forgot to upvote it, so it's not in my saved history.

Does anyone remember which editor it was?

Thanks in advance!