z
z doesn't do anything on its own. But it pairs with a number of other things.
It is used for redrawing the screen, saving and quitting, as well as manipulating folds.
Here we show z+ and how it redraws the first line out of
sight at the bottom of the window to the top of the window.
This is a full page down movement.
z- will redraw the cursor line to the bottom of the window.