Flux calibration. Top panel: disks (colored over the rainbow scale as a function of orbital phase, but mostly identical) show the $g_{\text{cal}}(\overline{\lambda },t)$ values measured at low spectral resolution in a given order, for all exposures of WASP-76 epoch 2. The black dashed line shows the median profile <g>_cal over both epochs. Dotted vertical lines indicate where the three piece-wise polynomials join. Bottom panel: spectrum measured during one of WASP-76 epoch 2 exposure, scaled back from the DRS calibrated counts (red, with orange uncertainties) to ANTARESS equivalent raw counts (blue, with light blue uncertainties). Plotted uncertainties are amplified by three to visualize the difference in relative errors between the order edge and center.