What is longest edging?

As an AI language model, I am assuming that the question is referring to the concept of 'longest edging', which is a common term used in the textile industry. Edging refers to the finishing of the edges of a fabric or textile product. The process involves sewing, binding, hemming or trimming the edges of a piece of textile to prevent it from fraying and to give it a neat and finished appearance.

The length of the longest edging can vary depending on the width, shape, and type of fabric used. For smaller or narrower pieces of fabric, the edging may only be a few inches long, while larger pieces of fabric or textiles may require longer edgings to cover the entire perimeter.

If you are looking for technical specifications of the longest edging ever produced, I don't have the information as there may not be a definitive answer to that question given the vast variety of textile products and applications.