What kind of cable is the green broadband cable for fiber?

Tried to set up fiber internet service with the self-install today, but the router did not ship with the green broadband cable.  Customer support (2020 number and chat) can't/won't ship one, the local AT&T stores don't stock it, and nobody can tell me what kind of cable it is-- phone, CAT5, etc.

Does anybody know what kind of cable I need to buy to complete the install?  Thanks!