Hm...
www.mychevybolt.com
Forward Collision Alert - Alerts you to impending collision so you can brake yourself. This warning comes just before Low Speed Forward Automatic Braking.
Low Speed Forward Automatic Braking - Automatically brakes the car to a stop to avoid rear-ending a car ahead of you.
Front Pedestrian Braking - Identifies and brakes for pedestrians that are in front of your car (in case you don't notice them).
2019 Chevrolet Bolt 4-door hatchback - small car
www.iihs.org
So since the Low Speed FAB can stop for the 12 and 25 mph test, it's not limited to just Low Speed.
Unless the Bolt now actually brakes when you are backing up, I think in short it is just that LSFAB is too long and confusing so the marketing department (which probably cmae up with LSFAB) now want to just call it AEB so people know what it is.