ADF of G31 hub-filament system defined by the rectangular region defined in Fig. A.1. Open circles represent the observed data, with the error bars indicating the dispersion. The best fit is shown by a solid line, and the dashed line represents the ordered component (a₂′l²) of the best fit. The dotted vertical line and the horizontal lines, respectively, represent the beam size (12.6″) and the expected value for random B field ((1−cos〈Δ_ϕ〉 = 0.36, Liu et al. 2022b).