This design will angle your wrist slightly, so that the weight of your hand will rest on the pinky side of the base of your palm (the hypothenar). Essentially a modified version of the same principles that vertical mice use in their designs.

The main ergonomic benifits:

1. shifts your forearm slightly; towards it's untwisted natural position (shifting from pronation towards neutral)
2. encourages proper wrist & forearm positioning 
3. makes uncomfortable/"extreme" wrist motions less stressful on the wrist and forearm

All other parts are stock configurations and can be found here

Side note: might be worth printing this part out of TPU to get a slightly softer feel