In the transparent pillars thread (which turned out to be just removed A pillar panel cover) R o b pointed out that looks like a side camera not previously discussed in one of the photos. First it has to be noted that on previous mules there has been external wiring in this area as well, and many have pointed out the outward pushed front side windows on many mule sightings (like a Model S window that is frozen and closes over the window trim), which could mean this is merely testing equipment and not something slated for a production vehicle - if, indeed, it is anything at all. In any case, I decided to take a look at this area in other photos as well: Picture 1 - Spied: 2016 Tesla Model X The potential "camera", which is reminiscent of the potential front corner cameras, also shows in the Palo Alto Model X mule video (on the right below) - which is, we assume, the same mule with different wheels: With the assumed front cameras, a side camera would of course be useful for a 360 degree around view. That said, competition mostly places these cameras in the side mirrors. This B pillar mounting would be unusual and would probably leave more of the immediate sides of the car "in the dark" from the camera view. It might be easier to keep clean, though, and offer better views in traffic. In any case, thank you, R o b for the new sighting.