In the BRAKE STATUS byte that the ABS computer transmits, bit 0 represents the state of the brake switch: 0 = OFF, 1 = ON. When set the light will be blue.
Bit 4 represents the following (according to the specification):
BIT 4 : 0 = NO BRAKE SWITCH ON THIS IGNITION CYCLE
1 = BRAKE SWITCH ON THIS IGNITION CYCLE
In case bit 4 is set, the light changes to red. This is just to provide information about the status of that bit, I have no more detailed info.
I plan to release a better manual soon, together with an update of Espritmon that uses virtual buttons on the display instead of the key commands. Will put it on the same download location.