Temporal evolution of metrics indicating the extent to which the magnetic field is force-free. Top panel: current-weighted sine between the current and the magnetic field (CWsin, purple). Bottom panel: magnetic flux with T_w <  −1 (orange), and with −1 <  T_w <  −1/2 (blue). The curves are plotted on different scales. The dashed vertical line in each panel indicates the time of the X9.3 flare.