How can I be getting updates on the location of my lost iPad if the device is WiFi-only, with no cell phone hardware?

I lost my iPad mini (current model, 5th generation, running iOS 14 beta), the model that is equipped only for WiFi. This is the model of iPad mini *without* any cell phone hardware. When I checked now using *Find My* on my iPhone, Apple reports contact with the iPad only a half-hour ago, showing a current location on the other side of the city. But I've not been on that side of the city for hours. Where I lost the iPad, there are no WiFi networks that I have ever given permission for the lost iPad to join. ➥ So how can Apple's server's be reporting contact with a Wifi-only iPad with no previously-joined WiFi network available? I understand that a WiFi-only iPad can *determine* its location by scanning for nearby WiFi routers. But how does a WiFi-only iPad *communicate* that location back to me via Apple if the iPad has no authorized WiFi network connection?