I had written that it is not required to be in tentative list if property wants to modify buffer zone which itself is minor modificcation of boundary
But we are not talking here of a modification to the Buffer Zone are we??
KSTraveler's observation and question was
KSTraveler: What is the news on the renomination of Calakmul and Campeche? Is it on Mexico's tentative list?
And it was a reasonable question - The extension of Calakmul is described in UNESCO documentation as "Ancient Maya City and Protected Tropical Forests of Calakmul
(extension and renomination under natural criteria)
So, there are at least new criteria even if the inscribed boundaries stay the same. As per OG 166 this would seem to have required that the extension of the site to include new criteria should have been registered on Mexico's T List. Yet, as far as I (and KSTraveler) can see it hasn't been so registered.
This has been hanging around since at least 2008 as well - when Mexico's renomination/additional criteria for 2009 was noted as being "incomplete"