It uses a 0.100" (2.54mm) square-pin grid on both pitch and row spacing, making it footprint-compatible with standard 0.100" IDC receptacles and many legacy backplane headers.
The 0.100" pitch is the standard breadboard grid — it gives you enough room for two traces between pads on a typical 1 oz copper board, but the 52 positions across two rows mean a 26-pin-per-row footprint that runs about 2.6 inches long. Check your board edge clearance before routing. At 110 V, the creepage distance across the unshrouded pins is adequate for most low-voltage digital and analog signals, but not for mains or industrial bus voltages.