Caller ID by name, how did they do it?

Today a received a phone call from a colleague of a known contact, and this caller wasn’t in my contact list (yet). But somehow it listed her name on the incoming call screen. I have never noticed such before. Often unknown numbers show just the number.

I thought that such name identifier required a listing in my contact list. Apparently not.

Can someone educate me how that could work? How did she (or the organization she works for) do that?

Thanks.