EBD is used by Subaru with the following meaning:
Some publicity that everybody has copied wrote:
This system controls the balance between front and rear brake forces to optimize braking efficiency across all vehicle loading and driving conditions. The system also promotes increased brake pad life.
So if you are driving with no load, then the unloaded back brakes get less pressure, but if you have a lot of weight over the back, then more pressure can be applied to the back and proportionally less to the front for the same braking effect.
The real-world effect (I have a car with it on) is that the rear braking force is maximised at all times giving less nose diving and sharper braking.