"This document provides specifications for existing TLS extensions. It is a companion document for RFC 5246@ ""The Transport Layer Security (TLS) Protocol Version 1.2"". The extensions specified are server_name@ max_fragment_length@ client_certificate_url@ trusted_ca_keys@ truncated_hmac@ and status_request."
RFC 6066-2011 history
2011RFC 6066-2011 Transport Layer Security (TLS) Extensions: Extension Definitions