Wi-Fi signals could prove useful for spies(economist.com)
economist.com
Wi-Fi signals could prove useful for spies
https://www.economist.com/science-and-technology/2023/01/25/wi-fi-signals-could-prove-useful-for-spies
https://www.economist.com/science-and-technology/2023/01/25/wi-fi-signals-could-prove-useful-for-spies
(These signals have been useful for a variety of people for over ten years.)