Thanks for the clarification, perhaps I was misleading, the point being that black holes have been deduced by mathematical interpretation, not observation of a phenomenon and today as per your own example we're still trying to find proof of their existence.
On the other hand, based on my understanding of the Janus model as I said in my first comment, the location of the seemingly void places are actually explained by the concentration of antimatter, which repulses matter through gravity.
A possibly wrong summary of what I'm visibly struggling to communicate:
This model explains how on the same way matter concentration attracts matter and rejects anti-matter, antimatter concentration attract antimatter and rejects matter.
On the other hand, based on my understanding of the Janus model as I said in my first comment, the location of the seemingly void places are actually explained by the concentration of antimatter, which repulses matter through gravity. A possibly wrong summary of what I'm visibly struggling to communicate: This model explains how on the same way matter concentration attracts matter and rejects anti-matter, antimatter concentration attract antimatter and rejects matter.