[Roadsters] "B" dash light - circuit to nowhere?

[nmleeds at mindspring.com]

Could someone tell me what the "B" dashboard light is for? The best I can figure the service brake switch on the dash turns it on and off, but it isn't hooked up to anything else--fun, but even I get bored turning lights on and off.

Is there some missing hardware that should connect this light to the parking brake? Should I wire it to the brake lights? 

Nathaniel Leeds
'69 2000 (electrically challenged)