Subalterno (property unit number)

On the cadastral map the building occupies a particella (parcel). Inside the building each property unit has a subalterno number: the flat on the second floor might be subalterno 5, the garage subalterno 12. Shared areas, such as the entrance hall and courtyard, can also have their own subalterno.

The identifier of a flat is therefore municipality, sheet (foglio), parcel (particella) and subalterno. You will find it in the visura catastale (the land registry record), in the cadastral floor plan and in the purchase deed.

Data on individual units (category, cadastral income, floor plan, owners) is not open data: you get it with a visura. That is why the report describes the parcel and the building, not the individual flat, and says so.