Since the stream has been on some starting screen for several minutes, I went to check whether there are watch-along streams on Twitch for this - there are a few, and for some reason every one of them is in Spanish. I know Spanish-language streams are a big thing, but it's curious that there's three Spanish GPT-5 watchalong streams (two with 50-ish viewers and one with 2.5k) and none in English.

edit: YouTube has a few English "watch party" streams, although there too, the Spanish ones have many times more viewers.