Copies it into the buffer, silently. No notification, nothing. Great UX.

In Ubuntu it's even better, it actually saves it as an image file (and does the annoying shutter effect). But the repeat key is not turned off... so if by any chance you hold it down by mistake, thinking it was the right ctrl, oh boy, you get a shitstorm of shutter effects and dozens of screenshots in the pictures folder. Very annoying. I don't know which I hate more, Ubuntu or Windows.