A reader (thanks, Krista) found it on Amazon. It is an egg box. My guess is that eggs in the UK are smaller than our large eggs because I got it out again and tried putting eggs in it and it’s just impossible to get eggs off that top shelf. If you look at how much space is between the top shelf and the bottom shelf, it makes no sense that the top shelf is up against the top.
Oh well . . we’ll see what Vince ends up doing with it.