The NavigatorGeolocation.geolocation read-only property returns a Geolocation object that gives Web content access to the location of the device.
The NavigatorGeolocation.geolocation read-only property returns a Geolocation object that gives Web content access to the location of the device. This allows a Web site or app offer customized results based on the user's location.
MDN
The NavigatorGeolocation interface contains a constructor method allowing objects implementing it to obtain a Geolocation instance.
There is no object of type NavigatorGeolocation, but some, like Navigator implements it.
MDN