I believe they just entity files for the little pips that show up in the horse-shoe icon around planets.  The thing that shows a rough estimate of how many of ships and modules are in that gravity well.  Unfortunately, they are NOT for the pips on the empire window (I know only because one little mod I had merged with another removed those, and it took me forever to find them to put'm back.  Those four files did NOT help with that in the slightest. Heh.)  Not sure on the planet one, though, unless it's used for the planet pips shown for a star.