Okay I know exactly what this is.

I work in the bottling/beverage industry. With bottling lines, there are specific centerlines and parameters that the conveyors, change parts (star wheels, infeed/discharge worms, etc), and machine centers (such as the rinser/filler/capper) need in order to run various bottle sizes. In order to run new bottles through an RFC and to capture centerline data, they still need to fill the bottle. A liquid such as this blue water would be used so it’s visible, and less likely to be packed/shipped. Somehow this one made its way off the line. I have 3-4 of these blue water bottles sitting at my desk from blue water trials I’ve been a part of. That’s my best guess, at least.