Only 22% did have any static site generator detected. Beyond that, 33% had a CMS detected. That leaves nearly half of analyzed sites as unknowns! Speculation a

Only 22% did have any static site generator detected. Beyond that, 33% had a CMS detected. That leaves nearly half of analyzed sites as unknowns! Speculation aside on what might be effective aside, the real answer wrt OP is basically "it wasn't".