There is another out-of-band way to handle this that a terminal host could implement (no OSC required)

- detect animation in the terminal (defined as changes without user input)

- when the animation stops it needs attention

- if it doesn't have the user's attention, ring some sort of bell

I built such a terminal specifically because this problem was driving me nuts. The marketing for it isn't finished yet (planning to launch next week) but it's been my daily-driver for months if you want to try it out: https://dormouse.sh/

But OSC 7501 seems like a great idea, I'll track its implementation here: https://github.com/diffplug/dormouse/issues/1079