What is it?

[Robson Valley]

That is/was the very best part of 4x5 sheet films = you can shoot and soup as many shots as you need.
I've done just one or two many times.
Same is true in this day and time but with digital. Take a shot. Look at it. OK? quit.

I wonder of that rack wasn't a place to dry calligraphy, watercolors or other inked artworks.

 

[Fadcode]

looks like its made to dry something in natural heat, as it doesn't appear to have a heating element or fan fitted to it, there are certain items that should be dried naturally for instance flowers, seeds, tobacco, cigars,and cannabis, as well as other things.
it also looks as if you don't have to keep looking at the objects that are drying, and you are not too worried about small particles falling from one shelf to the next one down, which gives the impression that nothing being dried is sensitive, like photo negatives etc, etc,
I would go for a tobacco/cannabis dryer.

 

[Paul_B]

The question should be, what are you going to do with it? Whatever that is then that's what it's for. Problem solved, answer found!

 

[dwardo]

If you look closer are there any stains, marks even smells lingerin? If it was a drying thing I would imagine there would be some spillage. Get the Mag class out and go all Clouseau.