On the desktop, it might be limited in the sources it has. GeoIP is one source, of course, but that's often wrong or too coarse-grained (or distorted by things like VPNs). The BSSIDs of nearby WiFi access points can help make that better, but that depends on you being close enough to APs in its dataset. Most desktops don't have actual GPS hardware.
Of course. But the desktop reports both estimated location and estimated accuracy. I'm complaining about the inaccuracy of the accuracy, not of the location.
