[crankylinuxuser]

It gets uglier, if the person who wrote this added in an underclocker.

https://hackaday.com/2019/01/04/underclocking-the-esp8266-le...

Long story short, underclocking the ESP12 compresses the RF envelope for 2.4GHz . It also means the RF energy is in what looks like 1/3 a normal 2.4GHz channel.

The awesome side effect is that this device's SSID is completely hidden from regular 2.4GHz radios. You need another ESP12 with the same underclock ratio... and then need the SSID (if hidden), and the password.

You'd be able to find it using an ADALM-PLUTO. It'd stick out like a sore thumb, but it still wouldn't make sense what's going on unless you build a decode stack in Gnu Radio.