Processing of the MIRI-MRS spectrum. (a) DF3: (Top panel) Spectrum observed with MIRI-MRS. The red line is the estimated continuum. (Bottom panel) Continuum subtracted spectrum. (b) Disk: (Top panel) Spectrum observed with MIRI-MRS. The red line is the estimated continuum. (Bottom panel) Continuum subtracted spectrum. All the observed lines are from ${\mathrm{C}\mathrm{H}}_3^{+}$ except for the highlighted ones. The identifications are made using Van De Putte et al. (2024).