I *think* the thing on the right is a drop bracket for the panhard bar, which is the axle link behind and parallel to the rear axle. The little tab on the left might be to raise the brake line junction on the rear axle, so you don't overstretch the center brake line with the lift.
I have no idea what the piece of blue unistrut is for...
Note that I have not used a Calmini lift, so take the above for what it is worth.