ISO/IEC 26134

OpenID Connect 1.0 is a simple identity layer on top of the OAuth 2.0 protocol. It enables Clients to verify the identity of the End-User based on the authentication performed by an Authorization Server, as well as to obtain basic profile information about the End-User in an interoperable and REST-like manner.
This document defines a mechanism for a Relying Party to request that an OpenID Provider log out the End-User.