Floating Viewpoint

To access this 3D view mode:

3D View ribbon >> Viewpoints >> View >> Floating.

A "floating" 3D window viewpoint is a unique item (for each 3D window that exists) in that it is, in essence, the camera that you use to view your 3D scene. It is the default viewing mode and lets you do useful things like:

Rotate the camera
Pan the camera

Note that the magnification of the view isn't, strictly speaking, a viewpoint function. It is simply the zoom level applied to the current viewpoint location and orientation.

Floating Viewpoint mode is cancelled when any other object or viewpoint is selected from the View list, or when Inside or Outside View is chosen for a 3D Object.