kCLLocationAccuracyHundredMeters constant

When leveraging the kCLLocationAccuracyHundredMeters constant, what GPS data is being used and where is it stored? The "last known location" used to be stored in cache.plist, but since iOS 4.2.8 that is no longer the case. How are the values being compared? Is the information in the cache.db being used and how is that precise given it is using Wi-Fi and cell tower locations?

Thanks!