On this vehicle, the front wheels are not aligned to the rear thrust line. This can happen from normal wear and stress, whether your vehicle has adjustable or non-adjustable rear suspension.
To steer straight ahead, you would have to steer the front wheels slightly to the right.
A common result would be that the vehicle would "dog track" and possibly "pull" to the
side.
Of course, the angles are exaggerated so you can more easily see the condition. But it takes only a small misalignment to create problems.