It should come from the service center where you filed your application. After stamping your passport, the local BCIS will send you I-89, EADs, APs, I-94s to the service center. Then your online message got updated with "card ordered" . BCIS has a so called Centralized Card Production Facility which prints EADs and GCs. So Service center will send the request to this facility to make you a GC once they are satisfied with your I-89 form and photos. The facility will produce the card according to the first come first serve logic and send the card back to service center and it goes to the mailroom to be sent out.
---Compaqdb