Tag Properties
Here you will find a link to the Capture object that defines the rotation of the object to which the tag is assigned.
This option defines if the left or right eye is selected.
If this option is enabled, the eye position and rotation directly from the ARKit data will be used.
If disabled, the eyes can be positioned manually, whereby the rotation will be calculated based on the Blend Shape value, which, however, is nearly identical to the ARKit (Apple's AR interface) calculation.