ECM and fuel pump relay control

[belaw]

Okay, one more trip to the well.... (this is what you guys get for being so helpful).

I finished stripping my harness and my (hopefully) last issue of confusion is with the 2 fuel pump relay connections at the ecm.

Pin A1 is listed on the 7747 wiring diagram as the "Fuel Pump Relay Control," which based on the diagram on top of the relay does exactly what the diagram says.

What has me stumped is the "fuel pump input" at B2; on my harness the wire taps into the wire from the switched output of the relay to the fuel pump, and as near as I can tell this wouldn't do anything other than tell the ecm that the fuel pump has power. Is that right? If so, why? More to the point, do I need or want the B2 fuel pump input circuit on a carb to TBI swap?

Also, when the relay is not energized the fuel pump input circuit is switched to another relay output (it would be pin 87a on a Hella/Bosch relay) that is shown as "fuel pump test" on the wiring diagram. What the heck is that?