The inurl:viewerframe?mode=motion&top string is just one of many. Security researchers use a family of similar "Google Dorks" to map IoT vulnerabilities.
Camera manufacturers frequently release firmware updates that patch security vulnerabilities, improve authentication mechanisms, and address configuration weaknesses. Regularly check for and apply firmware updates from your camera's manufacturer. inurl viewerframe mode motion top
This tells Google to look only for websites that contain specific text within their URL structure. The inurl:viewerframe