The only giant bolt I see on the end of the rear caliper that bolts to the fork is the axle?
Otherwise, there are 3 fasteners on the caliper. From L. to R. Pad pin, bridge bolt and bumper. But as you mentioned,what your asking is not referenced in parts manual. Can you give more info?
After looking at the rear wheel section of the parts manual, there is this giant bolt that goes through the rotor and it's referenced by number as the axle. So, I think I;m going with that. I think what your referring to are the upper bolts of the caliper that hold the pads in. Right?