I would like to be able to add free-form or list based field added to a device as an additional entity.
Specifically, I want to be able to add an additional entity to existing devices.
Once it is created, HA should interact with the field as with any other entity.
Example use: sensor.weathersensor.batterylevel tells me the percentage the battery is at. What kind of battery is it though?
I would like to add sensor.weathersensor.batterytype and enter the value CR2032 in it. Maybe it is a predefined list that I defined for this field (e.g. CR2477, CR2450, CR2430, AA, AAA, 9V), maybe it is freeform.