How did this develop? And how did what started out as one kind of animal — a formal identification tool — mutate over time into something rather different.
Listing had to be made as easy as possible, to encourage its use and reduce the temptation of creating “a list behind the list.” Process was kept to a minimum with — most notably — no formal notice to owners of properties listed (after all, it was just a list, right?).
Note 2: See “‘Cultural heritage’ and the fuss with definitions”, from January 21, 2016