What is the ruling regarding partial exposure of the foot while wearing foot coverings (khuff)?

Primary text

If the upper part of the foot covering (ظهارته) becomes exposed while the lining (بطانته) remains covering the foot, this exposure does not invalidate the ruling concerning wiping over the foot covering. This is because the foot is considered covered by what accompanies the covering in sale, thus resembling a situation where the covering was not removed or significantly damaged.