The former, it's a Xiaomi redmi note 9s
Nah they've had pop up windows for a while now. The note 4 had itThat would be a MIUI feature then, other phones based on stock Android don't have this feature.
As above other OEMs like Samsung does have it added, but as far as I'm aware, it's only when you use Dex mode for the desktop layout. Much more useful on a bigger screen like a tablet or external display.
Nah they've had pop up windows for a while now. The note 4 had it