To expand on what DEAN0 has correctly said above:
XDS uses the ABS system, specifically the ESP system, to apply braking pressure to the inside wheel when cornering to force the differential torque to the outside wheel. It's particularly effective when driving at medium speeds in low gears in closed or tight corners, longer sweeping corners it's less apparent.
The effective management of the drive torque causes corrective yaw torque which minimises the risk of understeer.
XDS - Non-Cupra
VAQ - Cupra