Just to clarify, this sounds like something my sister and I had to file in my father’s probate case. It isn’t directly about claiming your share, it’s about your knowledge of anyone else who might have an interest in the estate. Neither of us had seen my father in something like 35 years or more, so it would have been better to have someone else do it if such a person existed.
But, there wasn’t anyone, so it was all just to the best of our knowledge, he never had any other children, and was not married, nor were his parents still alive. I think it is just a way of identifying who could possibly have an interest in the estate so they will have notice and the ability to take part if they want to.