The description attribute gives a textual description of the variant. It can be included if the URI and normal attributes of a variant are considered too opaque to allow interpretation by the user. If a user agent is showing a menu of available variants compiled from a variant list, and if a variant has a description attribute, the user agent SHOULD show the description attribute of the variant instead of showing the normal attributes of the variant. The description field uses the UTF-8 character encoding scheme [5], which is a superset of US-ASCII, with ""%" HEX HEX" encoding. The optional language tag MAY be used to specify the language used in the description text.