The extensible resource descriptor sequence (XRDS) is an XML-based file format that provides a list of services.
The acronym XRDS was coined during subsequent discussions between XRI TC members and OpenID developers at first Internet Identity Workshop held in Berkeley, CA in October 2005.
The protocol for discovering an XRDS document from a URL was formalized as the Yadis specification published by Yadis.org in March 2006.
[2] In early 2008, work on OAuth discovery by Eran Hammer-Lahav led to the development of XRDS Simple, a profile of XRDS that restricts it to the most basic elements and introduces some extensions to support OAuth discovery and other protocols that use specific HTTP methods.
The OASIS XRI Technical Committee has operated since its inception in 2003 under a royalty-free licensing policy as stated in its charter and IPR page.