Did we ever find out what they were?

I just remembered that the brackets in the title were supposed to be significant according to Aka, and that we’d eventually find out what they meant. I vaguely remember that the star eyes eventually got explained in the manga itself, but I don’t remember him following through on the explanation of the title. Did I just miss it? Was there supplementary material that did so and I missed that? I remember us speculating about it, but don’t know if Aka confirmed anything in the year and change since the manga ended.