I Know That Jags are Pretty Special

While browsing an admittedly old catalog for a detailed drawing of the headlight assembly for a Jaguar  XK140, I ran across this unknown-to-me requirement for their headlights.

 

This shot is from the index section of a 1992 XKs Unlimited parts catalog and it shows an entry for "Headlight Fluid". Turning to page 51 in the publication to further my education on these exotic beasts, I found no mention of of this elusive liquid.

There are descriptions of Jaguar's styling as "fluid" and I've even seen a website dedicated to "blinker fluid", but this one is new to me. Was this simply an "Easter egg" prank or perhaps a place holder during the design of the catalog?  

There is one more oddity in the photo that I didn't mention. See if you can find it and then drop me a note in the comments section.