[VAC] What is this?

["David W. Lowrey" <dave_lowrey@xxxxxxxxx>]

In the side of the sink cabinet in my '77 Sovereign is a "cubby hole". It's 
main purpose in life is to cover up the service access hole for the water 
pump and Everpure water filter.

But, I was wondering what, if anything, it's designed to hold? Why didnt 
they just put a plate over the hole?

Here is a photo: http://w3.one.net/~dlowrey1/airstream/aspocket.jpg

Any ideas?

Dave