The rotation of the inertia tensor.

If you don't set intertia tensor rotation from a script it will be calculated automatically from all colliders attached to the rigidbody.

	// Resets the inertia tensor to be the coordinate system of the transform
	rigidbody.inertiaTensorRotation = Quaternion.identity;

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    void Example() {
        rigidbody.inertiaTensorRotation = Quaternion.identity;
    }
}

import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	def Example() as void:
		rigidbody.inertiaTensorRotation = Quaternion.identity