I see most of the doors are there

I don't have any private key. That is just my id.

With that tag I get notified when there is a change

Hi, this is a very old changeset. I think I was following this: osm.wiki/Proposed_features/IndoorOSM

The import is (and was on the wiki): osm.wiki/Lombardia_ToDo#Importazione_dei_dati_della_provincia_di_Lodi, which link to osm.wiki/Lombardia/Import_Database_Topografico_Lodi. As written in the page: "Italian Open Data License (IODL) 2.0., so usable in OSM"