A few SDN-detailed pools continue to have an “operator” authorization. Of such, two belong to incredibly old, now-unused variations of Tornado Cash. The remaining pools possibly have more recent, immutable variations, or have been applied so little they were being very likely overlooked through the May possibly 2020 last update. https://mainecunatic.com/the-ultimate-guide-to-tornado-cash-secure-and-anonymous-blockchain-transactions/