[email protected] seems incorrect
[email protected] is broadcast in the beacons from
"ibeacon:*,altBeacon:* and eddy:*" devices. So if those are not correct you need to fix the beacon to send the correct value.
For all other devices [email protected] is the setting plus an offset to correct for broadcast power. See https://github.com/ESPresense/ESPresense/blob/master/lib/BleFingerprint/rssi.h for the exact values.