It seems to based on advertisement data, particularly the manufacturer data:
4C00 02 15 585CDE931B0142CC9A1325009BEDC65E 0000 0000 C5
<company identifier (2 bytes)> <type (1 byte)> <data length (1 byte)>
<uuid (16 bytes)> <major (2 bytes)> <minor (2 bytes)> <RSSI @ 1m>
I have this node.js script working on Linux with the sample AirLocate app example.