Data gathering in Firefox for Android is optimized to have little battery cost and no mobile data plan usage. It sit and waits until other applications on the phone obtain GPS-based location information, for example Google Maps. The battery impact of using the GPS sensor is so large, that anything else you do at the same time is basically not noticeable. When some other application get a GPS based position, our data gathering code gets activated as well and initiates a scan for nearby cell and WiFi networks. Often enough the other application will have also caused those, as part of getting a location fix, so there’s almost no additional battery cost that can be attributed to our code.
Finally with the GPS position and the cell and WiFi networks in hand, our code stores those locally on the phone. There are also a variety of rate limits in place, so we don’t collect too often and not more than a certain amount per day.
Once the phone connects to a WiFi network, the locally stored data is uploaded to our service, avoiding mobile data plan costs.
The phone won’t collect more data, when it already has reached its total quota and wasn’t able to send data to us, so it won’t spam the local disk.
Currently there are no configuration options to change any of those default settings, as that would defeat the simple “opt-in and don’t worry” model we choose. If one wants more control, the dedicated Mozilla Stumbler app is there for you.