[Name] maxstale [Type] An unsigned integer [Required] No [Default Value] None [Description] 
Indicates that the document is willing to use content that has exceeded its expiration time (cf. 'max-stale' in HTTP 1.1 [RFC2616]). If maxstale is assigned a value, then the document is willing to accept content that has exceeded its expiration time by no more than the specified number of seconds.