Nomura Research Institute GREE, Inc. CA Technologies This specification defines an extensible metadata framework that may be inserted into the OAuth 2.0 responses to assist the clients to process those responses. It is expressed either as a link header, or query parameters. It will allow the client to learn the metadata about the particular response. For example, the client can learn where the members in the response could be used, what is the characteristics of the payload is, how it should be processed, and so on. Since they are just additional response header/query parameters, any client that does not understand this extension should not break and work normally while supporting clients can utilize the metadata to take the advantage of the extension.