From the XDG mailing list:
From: Federico Mena Quintero <firstname.lastname@example.org>
Subject: File manager DBus interface
To: xdg <email@example.com>
I've just created this page to document the file manager interface that
we discussed some months ago:
Sorry that this took so long to put up!
If you have any doubts, he's quite a nice guy and you can find him often on #opensuse-gnome (federico1).