Related to OwnTracks I suppose... how does Google Maps on iOS know where I parked my car, if I've set it only use my location 'whilst I'm using the app' and I haven't used the app to navigate to my parked location?
As long as it has a location lock when you last were in your car, that's sometimes a good enough signal for "parking location" for Google. If you have location on for any other Google app/website I'm guessing they use that as well.