Never tried that. Will see what happens when I get home to my iPad. In all previous versions of iPadOS, it was a swipe up from the bottom (or, of course, a tap of the home button).
I checked. Swiping down from the top of the window gets rid of it but doesn't exit the app (it minimises it). The app is still available in exposé if you swipe up a short way from the bottom of the screen. So basically:
- Flick up to make window full screen
- Flick left to pin to left side
- Flick right to pin to right side
- Flick down to minimise.