#Neostumbler collects the data in the first place. While databases like #MLS (Backups), #OpenCellID and also Apples exist and are easily available, #BeaconDB only uses newly gathered data.
Neostumbler takes the real GPS location together with nearby Wifis, Cell Towers and Bluetooth beacons. These datasets get uploaded, and shortly after, clients like #geoclue or #microG that use BeaconDB, can find a location there.
Neostumbler shows an overlay map for existing data