Continuum-subtracted spectra, zoomed in on C₂H₂ and ¹³C¹²CH₂ (left-most column), the HCN Q-branch and hot branch (second column and third column), the CO₂ Q-branch, ¹³CO₂, and CO₂ hot branch (fourth, fifth, and sixth column). The respective features are highlighted in yellow, orange, or green, and prominent H₂O features are highlighted in blue. The spectra are once more ordered from largest to smallest ${\text{H}}_2\text{O}/L_{\text{acc}}^{0.6}$ from bottom to top. Note that in the fifth column, the highlighted H₂O feature has been subtracted to uncover a potential ¹³CO₂ feature. The rescaled spectrum of DR Tau is included in pink for comparison.