there was a thread a whole back on Southern Downhill, where the Juice Lubes bloke explained what it is. (also linked on one of the other previous threads on this on stw iirc).
It is silicon lube with a fancy label and a markup, but it is a particular form of it they use in the glazing industry rather than your standard halfords dashboard stuff. The difference is allegedly that the ‘glazing’ one has extra stuff in it to help move big sheets of glass sideways under the heavy weight of a whole sheet. The idea being it allows your uppers to move more smoothly in and out of your lowers under the pressure of actual riding ‘forces’, and does this better than ‘standard’ silicon lube. I expect if you were in the glazing trade you could source it for much less per can, but where would you find it?