When navigating the 3D view in orbit mode, you can click and hold to rotate the model around a point. Two options are possible to define the position of the center of rotation: the center of the 3D view, or a point that you choose by clicking. This is recommended for models with small geometry or with a lot of space between components.
To switch from one option to another, you can go to Extra > Settings > Navigation. When the option "Click defines center of orbit" is disabled, the center of rotation will be the center of the 3D view.