expiration

If the expiration is configured for the object (see PutBucketLifecycleConfiguration) in the Amazon S3 User Guide, the response includes this header. It includes the expiry-date and rule-id key-value pairs that provide information about object expiration. The value of the rule-id is URL-encoded.

Object expiration information is not returned in directory buckets and this header returns the value "NotImplemented" in all responses for directory buckets.