Android 'improve location accuracy' seems to hunt for previously geocoded wifi beacons, to locate those people who have their phone GPS disabled. It's surprising to me how people are willing to allow their phones to send this info to data brokers.
I don't know if this is still the case as I don't see a high accuracy option in settings anymore.
Sorry can't find better sources. Just personal experience and: https://forums.androidcentral.com/samsung-galaxy-note-3/5023... https://forum.xda-developers.com/t/location-mode-sets-to-hig...