This is the geolocation window.

It will appear each time you move the cursor. This is called cursor-mode, and the geolocation window confirms that you switched from flight-mode to cursor-mode.

Move the cursor to another place, and the information it contains will change, displaying those right under the cursor.

It gives you the latitude, longitude, orientation related to your present position, and distance from your present position.

As long as it remains displayed, your map stop moving. To come back to your present flight position and flight-mode, you will need to press CLEAR to make the cursor and this geolocation window disappear.