jabber:x:envelope

This extension allows clients to express to each other identities and message recipients in a rich way. Full names or nicknames can be sent, message forwarding headers, requested reply-to addresses, etc. It is often used within server-side functionality to note when messages are forwarded. The server otherwise does not use this namespace for actual routing or delivery purposes, that is entirely client-side.

<x xmlns="jabber:x:envelope">
  <to jid="user@server">John</to>
  <cc jid="foo@bar.com">Some guy</cc>
  <replyto jid="asdf@asdf.com"/>
  <from jid="me@here.now">The Thing</from>
  <forwardedby jid="admin@server">administrator</forwardedby>
</x>