According to [0] the "data comes from a variety of phone applications—such as gaming or weather apps." Their opt-out policy [1] confirms that since it requires

According to [0] the "data comes from a variety of phone applications—such as gaming or weather apps." Their opt-out policy [1] confirms that since it requires a mobile advertising identifier. It seems like they can only collect data from mobile devices. [0] https://georgetownlawtechreview.org/the-government-has-your-phone-location-data-it-might-be-legal-but-what-does-it-mean-for-your-privacy/GLTR-03-2020/ https://georgetownlawtechreview.org/the-government-has-your-... [1] https://www.venntel.com/opt-out https://www.venntel.com/opt-out