The US Department of Justice has demanded that Apple and Google provide personal data on over 100,000 users of the EZ Lynk Auto Agent app, which is allegedly used to bypass vehicle emissions controls. The app's manufacturer, EZ Lynk, denies the allegations and argues that its products serve legitimate purposes. The DOJ claims it needs the information to identify and interview witnesses who can testify about how the tools were used. The request has raised concerns about user privacy and the potential for government overreach.