JetBlue:
B6 Inflight received an update to onboard announcements citing the name change from Core to Main.
OLD: "We now invite you to sit back, relax, and stretch out - you've got the most legroom in coach. Thanks again for flying with us."
NEW: "We now invite you to sit back and relax. Thanks again for choosing Jetblue."
Pretty obvious this isn't about the name change, really. It's dancing past the reduction of legroom in Main to add First Class and can therefore no longer claim the most legroom in coach.