Toolkit allowing to sniff and display the Wi-Fi probe requests passing near your wireless interface.
Probe requests are sent by a station to elicit information about access points, in particular to determine if an access point is present or not in the nearby environment. Some devices (mostly smartphones and tablets) use these requests to determine if one of the networks they have previously been connected to is in range, leaking personal information.
Further details are discussed in this paper.
pip3 install --upgrade probequest
The project is documented here.