Assuming this comment is made in good faith, it's referring to the fact that it can be delivered in a "flat package", so to speak, and has to be assembled by th

Assuming this comment is made in good faith, it's referring to the fact that it can be delivered in a "flat package", so to speak, and has to be assembled by the customer. Flat being a relative term, rather than a specific width. This is the relevant wikipedia article: https://en.wikipedia.org/wiki/Ready-to-assemble_furniture https://en.wikipedia.org/wiki/Ready-to-assemble_furniture