During the betas of Windows Vista, the final set of sample logon pictures had yet to be determined, so a bunch of placeholder bitmaps were created. These placeholders consisted of the letters FPO in a box. FPO is a standard term in desktop publishing; it stands for For Position Only. In order to permit designers to perform page layout before final images are ready, a For Position Only image with the correct size and shape (but dummy contents) is used. I learned it as For Placement Only, but the meaning is the same.
We received a bug report from a beta tester in Austria who was surprised to see what appeared at first glance to be the name of the FPÖ political party as several of the logon picture options. Was Microsoft taking sides in the political affairs of Austria? No, it was just a coincidence.
I suspect the designers learned their lesson: Don't use publishing jargon in bitmaps, even if it seems harmless.