When I soften my focus I see that the field is compartmentalized by the clever and subtle (until you see it) drawing of at least one horizontal line. It is between the first and second register of major Guls.
1) The line is coincident with the abrash in the red ground from dark to less dark.
2) Follow the line out to the right and left borders. It is continued by the white lower borders of the two brackets (which comprise the lower half of the main border design element).
3) Note the use of white in the minor design elements which are asymmetrically bisected by the line. The upper half of these elements sit right on the line and further define it.
4) The line is buttressed by the darkening of some of the horizontal (blue/brown?) superior and inferior outlines of the Guls in the first and second registers.
I bet that Shiv would consider this an example of the phenomenon he described. Shiv, are you out there?
Does it signify anything? After you've looked for awhile, you will see this kind of thing often enough that you will certainly start to wonder. That is, if you haven't already.