In the table of Maximum Configuration Time Estimation for Intel® Stratix® 10 Devices, what do 170-230MHz internal clock and 250MHz internal clock represent?

The Clock parameters 170-230MHz internal clock and 250MHz internal clock in the table of Maximum Configuration Time Estimation for Intel® Stratix® 10 Devices represent the clock for SDM operations.  The frequency depends on the setting of Configuration clock source in Intel® Quartus® Prime Software.