Can literally be a "Desk ID" basically, so using that would reach the phone next to the agent. Used to work both with outgoing cold calls and incoming customer support, had a setup that worked like that for the latter.

Didn't use it, it was fixed, so I don't have more details, sorry.

Enedis is basically a state owned company (to be clear, they aren't the one selling electricity, they are the one in charge of the network and the distribution, so I'm not sure if it counts as utility).