Where in the code is the program scanning for access points and signal strengths

[chensteven]

Can someone kindly point me to it?

[chucklin85]

That is in the client software that you use for FIND. For example, on Android, the client grabs this information via the API provided by Android and then it is passed back in a JSON object to the FIND server.

For example:
https://github.com/schollz/find/blob/android/main.js
Line 166 onwards