rfc-4467
Internet Message Access Protocol (IMAP) - URLAUTH Extension
This document describes the URLAUTH extension to the Internet Message Access Protocol (IMAP) (RFC 3501) and the IMAP URL Scheme (IMAPURL) (RFC 2192). This extension provides a means by which an IMAP client can use URLs carrying authorization to access limited message data on the IMAP server.
An IMAP server that supports this extension indicates this with a capability name of "URLAUTH". [STANDARDS-TRACK]