[Question] more than two colors for empire flags?

[Zelootti]

I noticed that the colors section of empire_flag fields in 00_prescripted_countries.txt and user_empire_designs.txt looks like this:

colors={
       "dark_grey"
       "black"
       "null"
       "null"
}

The game seems to use only the primary and secondary color, but the 3rd and 4th are always null. Does this mean it would be possible to have empire flags with up to 4 colors or are those just completely obsolete fields?