@BTDEVICELASTSEEN is a TCC function that returns the last time the Bluetooth device whose index is n was seen.
@BTDEVICELASTSEEN[n] : Returns the last time the Bluetooth device whose index is n was seen. Indexes range from 0 to %_btdevicecount. The format of the date is "mm/dd/yyyy hh:mm:ss".
Example:
echo %@btdevicelastseen[0]
06/12/2021 15:22:40