What this deployment can be asked about, what it cannot answer, and the rule for reading an empty answer.
A constant, and deliberately not a query: the index is the CONTRACT, and a contract that changed with the data would let an operator conclude that a category they cannot see does not apply to them.
One page of one category.
Every category's first page, for a caller sweeping the whole deployment.
The deployment's read-only work inventory over one D1 database — the same database its runs, approvals, and fence live in, so what it reports and what the fence governs cannot be two different deployments.