It looks and feels a hellavalot like plastic, but it's not. Not even close. It is a 100% biodegradable, home-compostable shipping satchel and is made from 70-80% PBAT (a co-polymer that is completely biodegradable) and 20-30% PLA (which is a fancy way of saying cornstarch).
In a commercial compostable environment, it will break-down within 90 days. At home, it may take up to 120 days.