In this case, it's a cheap-ish letter tray serving as a kind of poor (wise) man's docking station. I came across the letter-tray-as-laptop-stand ... is flush with a table. I'd also guess that ...

Alternatively, you can turn your bed into a desk with this handy Kmart tray table and really win at life ... Kmart folding tray that is the perfect laptop-bed desk. The brilliant concept comes ...