What is coffee silver skin? A coffee chain states that its paper napkins are made of "coffee silver skin":



The explanation on the right says it is "coffee bean skin"---the husk.

Searching the internet about it, I can just find about silver skin in meat.

Is there more to know about "coffee silver skin"? For example, I wonder if all or part of the husk is part of it, and also why the term is "silver" (this could be a different question---please comment or ask it yourself).
Silver skin is the name generally used when it is still on the green beans.  This thin but tough layer is lightly colored (sometimes similarly to the paper product in your question) and mostly translucent.  It allows the green color of the bean underneath to be seen.  After roasting (when it begins to loosen and fall off) it is more properly called chaff.

Since the paper is likely made of chaff collected from the roasting process (easy to collect since nearly all roasters have a mechanism for separation) is actually an excellent reuse of chaff.  "Chaff paper" just doesn't have the same ring since generally chaff is thought to be a byproduct to be discarded.  

The silver skin is the innermost layer of the coffee cherry surrounding the pit/seed (green coffee bean).  It is a tough substance to remove and different processing techniques remove varying amounts (dry process coffee removes the least and dry process coffee produces the most chaff when roasting).  Roasting the coffee both dries the silver skin and causes it to split as the coffee bean expands, so it comes off fairly easily during the roasting process given some agitation.