It gives you more trail. The trail is measured from a line down from the steering head pivot to the ground, paralleling the fork tubes (usually parallels the tube, some forks differ) to the ground. Drop a vertical line to the ground from the axle center and the distance from where the steering axis line and the axle line are on the ground is the trail. Hence, move the axle back increases the trail. Gives a more stability and slower steering.
As for bittercreek's query. It should improve things on the C5.
Bare