Good article, seems to represent the paper well which can be found here.<p><a href="https://www.researchgate.net/publication/375744216_Do_Black_Holes_have_Singularities" rel="nofollow noreferrer">https://www.researchgate.net/publication/375744216_Do_Black_...</a><p>Basically, as I understand, Kerr thinks it's most likely some kind of star at the center of a black hole.<p><pre><code> "The Kerr metric shows that there will be a region between the event shell and the central body where an eagle can fly if it flaps its wings hard enough. It will, of course, notice the outside universe spinning very quickly around it. It may also have a problem with the radiation building up between the star and inner horizon."</code></pre>