Vertical cross-sections, which correspond to the blue boxes in Fig. 2, of the T_w twist metric map at x = 0 Mm, showing a complex but connected structure that likely consists of two separate FRs. The lime green dots indicate the location of the axes for the upper (left) and lower (right) FRs. The T_w contours have slightly different thresholds in the left and right panels to highlight the two T_w maxima. The dashed green curve separates the almost self-contained T_w ≥ 1.0 region used by Price et al. (2020) on the right from the rest of the structure as described in Sect. 3.1.