Nope, it’s sponge storage. They were all the rage back in the late ‘80’s and early ‘90’s. (My previous life was as a draftsman for custom cabinet manufacturers)
I was guessing the kitchen was no newer than say, 1975.
My parents had one of those installed, but with a plastic drawer, when they got new cabinets in 1991.
They kept small screwdrivers and other tools in it that were handy around the house. I can’t imagine my mom putting a wet sponge in there with little air circulation. It would’ve given her the heebie-jeebies.