To see an overview of the entire map, press and hold the Control, Option, and Command keys (^+⌘+⌥) simultaneously.
To zoom to a different part of the map from the overview, move the mouse cursor to the area of the map in which you are interested before you release the ^+⌘+⌥ keys.
From v11.6.0, when using the zoomed-out overview mode, the portion of the map that is normally visible is now highlighted. In addition, the zoomOut:/zoomBack animation is skipped for complex maps, as it is too slow to be helpful.
See also—notes linking to here: