Bug Report MRUK 83.0.4 -> 85.0.0 _cameraAccess.GetCameraPose() bad

It looks like you shifted from "headpos" to "camera.main" in everything.
But... _cameraAccess.GetCameraPose()  is still using HeadPos which... was somewhere near my chest?

To reproduce:
Take CameraKit demonstration for QR codes.  Run with 83.0.4 in an unmapped space.
Works fine, the green quad covers/is close to the QR code.

Now copy/paste the code/objects into a newly set up 6003.9f1 project with MRUK85.0.0.  Run again in an unmapped space.  The QR is off.  The green quad is someplace else.  if you put tracers and debug flavor in, you will find that -- at least Y is ~34 cm off (look at CP)...
Debug Spice:

    private static Ray BuildWorldRay(QrCodeResult result, Vector2 uv)
    {
        var viewport = ToViewport(uv);
        var intrinsics = result.Intrinsics;
        var sensorResolution = (Vector2)intrinsics.SensorResolution;
        var currentResolution = (Vector2)result.captureResolution;
        if (currentResolution == Vector2.zero)
        {
            currentResolution = sensorResolution;
        }

        var crop = ComputeSensorCrop(sensorResolution, currentResolution);
        Debug.Log($"V {viewport} ");
        Debug.Log($"I -{intrinsics.PrincipalPoint} - {intrinsics.FocalLength} ");
        Debug.Log($"C {crop}");

        var sensorPoint = new Vector2(
            crop.x + crop.width * viewport.x,
            crop.y + crop.height * viewport.y);
        Debug.Log($"S {sensorPoint}");
        var localDirection = new Vector3(
            (sensorPoint.x - intrinsics.PrincipalPoint.x) / intrinsics.FocalLength.x,
            (sensorPoint.y - intrinsics.PrincipalPoint.y) / intrinsics.FocalLength.y,
            1f).normalized;
        Debug.Log($"CP {result.cameraPose.position} R{result.cameraPose.rotation}");

        var worldDirection = result.cameraPose.rotation * localDirection;
        return new Ray(result.cameraPose.position, worldDirection);
    }

To Fix:

    private async Task<CaptureFrame?> AcquireFrameAsync()
    {
        while (true)
        {
            if (_cameraAccess && _cameraAccess.IsPlaying)
            {
                var texture = _cameraAccess.GetTexture();
                if (texture)
                {
                    return new CaptureFrame
                    {
                        Texture = texture,
                        Pose = TMJGetCameraPose(), //_cameraAccess.GetCameraPose() is off...
                        Intrinsics = _cameraAccess.Intrinsics,
                        Resolution = _cameraAccess.CurrentResolution
                    };
                }
            }
            await Task.Delay(1000/fps);   //16=60fps
        }
    }

    private Pose TMJGetCameraPose()
    {
        var headPose = new Pose(_cmain.transform.position, _cmain.transform.rotation);

        // Apply VisionKit lens offset in head-local space
        Vector3 cameraPos = headPose.position + headPose.rotation * _cameraAccess.Intrinsics.LensOffset.position;
        Quaternion cameraRot = headPose.rotation * _cameraAccess.Intrinsics.LensOffset.rotation;

        // 4. Compose final camera pose
        return new Pose(cameraPos, cameraRot);
    }

And in Start(), _cmain = Camera.main();

Result:

Now the green quad is in the same place as it was in the Example code that uses 83.0.4

Yay!