I don't recall having seen any explanations for this. Has anyone ever seen anything like this elsewhere? It looks like two "tails" coming out of a central point, but I have no idea what the intention may have been. I'm also not sure if the "tails" angle is a good one, since the outer lines seem to make two half circles towards the cloud bands.
Conceptually, we can probably assume this scene takes place either in the sky or in the heavenly realm (or both). It is probably something you cannot touch when you are on earth, at least that would be the meaning of the cloud band in standard iconography. They also used a special method of painting, applying curved dabs of blue paint, maybe suggestive of clouds?
There is also a strange detail of a couple of lines bottom left on the inner circle.