Reproductions of the CMDs (left and middle panels) and the ChM (right panel) for the proper-motion-selected NGC 6397 cluster members from Figs. 9 and 10 are presented. Stars selected from the ChM are color-coded, with light-green and light-red representing 1P and 2P stars, respectively. Isochrones from the BaSTI database (Pietrinferni et al. 2021), with the same iron abundance ([Fe/H]=−2.02) but varying the oxygen content of [O/Fe]=0.4, 0.1, and 0.0, are shown in black, blue, and purple, respectively. These isochrones represent 1P stars, and 2P stars with intermediate and large oxygen variations. Segments of the isochrones with 19.8 < H_E < 21.5 mag are highlighted as large triangles superimposed on the ChM. Teal and crimson large dots overlaid on the CMDs represent the fiducial lines for 1P and 2P stars, respectively. The crimson dots in the insets of the left and middle panels indicate the color differences between the fiducials of 2P and 1P stars, δ(Y_E − H_E) and δ(I_E − E_E), at various H_E magnitude levels. The color differences as a function of magnitude for the O-intermediate and O-poor 2P isochrones are also displayed.