I have an Aqara water leakage sensor that (thank god 
) almost never sends status changes.
I’d like to know if this sensor stopped working and has not connected the Zigbee coordinator for a long time.
In the UI I can see a field named “Last Seen:” that contains the value I am interested in:
But there seems to be no way to access this value from with the code.
I managed to use templating to access some values, like for example this one here:
{{ states.binary_sensor.lumi_lumi_sensor_wleak_aq1_0ac73206_ias_zone.last_updated }}
The problem is: water leakage sensors, or smoke detection sensors, change their state only very rarely - hence the “last_updated” (or “last_changed”) values are not useful for my purpose.
My question: Where does the UI get the value of “Last seen” from? Can I access this value in the templating?