We don't know what these are. Really. Maybe you should go ask around on the forums, where they are posted, hopefully with any regularity.
(As you can see, we're missing some of them. If you have them saved, please contact anyone from the team, or post them on the forums. Thanks!)
Featured pictures from back when we still knew about what we were doing. These actually have some explanation about what's in them.
Ye Olde Trayler
The original, now almost a decade old, Machina Terra trailer. Don't expect much. No, we don't remember which codec it uses either.