Wow this is all so interesting! Unfortunately OneWorkbench, there is no slide out. It's probably an optical illusion in the photo. The rounded part is the top part, and the recessed area is below (where the tops of the doors close, is the best way I can describe it).
I'm beginning to think you folks are correct and this was two pieces formed into one. The top part is very reminiscent of the top of a hutch (with the rounded area at the bottom).
My aunt was quite an interesting person.... she was the "black sheep" of her big Irish family growing up (LOL) and had many varied friends of different persuasions; in other words, she was way ahead of her time. She moved around quite a bit and I believe this particular piece of furniture may have been taken on "large item trash day" from a neighbor's house!!
I actually love the weirdness of the piece and have used it for lots of things throughout the years. I love the idea of using the bottom for quilt display! At one time when my mom was living with me, we had collectibles displayed in the lighted bottom portion, but the shelf it set in such a way that everything in there has to be really small (short) in order to be seen.
I'm fascinated by this discussion... thank you!