Level 2 HELP needed from Wikidata Tech team... :)
Ettore,
I saw you experimented with adding it to Identifiers, and I also did... it seems it did not help give a clickable link via Formatter URL.
Another interesting thing I saw was that it threw a Single Value Constraint error...even though it is a single value "C81239"
So I think something is buggy somewhere with this P1748 property....and why I am asking for help from Wikidata Tech team. :)
-Thad