I agree with 1 because there is no workaround to finding them other than fetching every kind 30001 and filtering and disagree with 2
I disagree with 2 because the list might claim it has kinds X, but it might not, so the client should not depend on what the list claim it has
But wrt #1; it’s essentially the same thing I proposed for the c tag for categories and there wasn’t a lot of buyin so 🤷♂️