It’s similar in concept to the IPK, sniper designed, independently adjustable caster camber kits.
They use different bushings in the image below to adjust caster, and the screws to adjust camber (which is more easiliy measured).
The original sniper system that is used by CRG and others has notches for caster with each notch corresponding to a degree (i think). Plus you don’t have to take the whole spindle apart to change it, you loosen and adjust.