Some documents didn't clearly mention that they are under the GNU Free Documentation License. In order to respect this license a document must "contains a notice placed by the copyright holder saying it can be distributed under the terms of this License." (see http://www.gnu.org/copyleft/fdl.html, first section).
Hmm, I am guessing that this is the case, seemant? //ZhEN
We are actively working on a licensing format at this time. We are reluctant to release under the FDL, but we are exploring all solutions. //ZhEN