Very basic carbons support is hacked into mcabber. Messages are now intercepted and parsed. It probably makes more sense to implement XEP-0297: Stanza Forwarding in a more general way. A better way to display the carbons (so the user actually knows it is a carbon message) is in the pipeline.

[Desktop Entry]
Encoding=UTF-8
Type=Application
Name=MCabber
GenericName=Jabber IM Client
Comment=Console Jabber Client
Exec=mcabber
Terminal=true
Categories=ConsoleOnly;System;Network;InstantMessaging;Chat;