This answer points out this page
from Millennium Falcon Haynes Manual which refers to the two projections on the bows of all YT-1300 Correlian Freighters as mandibles.
According to the book "Incredible Cross-Sections of Star Wars: The Ultimate Guide to Star Wars Vehicles and Spacecraft", the mandibles hold various sensors and an anti-concussion field generator. Three is also the freight barge clamp so the YT-1300 can act like a barge or tugboat and push around large cargo. Also on the port mandible there is the shield generator and projector. On the inner side of the mandibles there is a freight loading arm. Click on the image to see a larger version.