There's a new editing unit, the subframe: 1/80th of the duration of a frame! That means if you are editing 1080p60 content, you are stepping back and forward 1/4,800th of a second. The specs say that the smallest value for a subframe is 1/192,000 of a second!
You can step back and forward, nudge audio back and forward (creating a split edit) and more in subframe and 10 subframe units.
There also keyboard shortcuts for all subframe navigation and nudging.