Spectra of B1-c (top row) and L1448-mm (third row) and the main spectral features detected among the JOYS data of these two sources (two panels per source below the full spectrum). In the top spectrum of B1-c, the SED continuum fit is shown in red and dominant ice and silicate absorption features are labeled in blue and brown, respectively. The two gray boxes mark the spectral range covered in the two insets in the second row. The baseline-subtracted absorption spectra of B1-c are presented in the second row, highlighting the CO and rovibrational H₂O features between 4.9–7.0 µm and the CO₂, ¹³CO₂, C₂H₂, and HCN features between 13.3–15.9 µm. The third row shows the spectrum of L1448-mm with dominant emission lines of H₂, [S I], and [Fe II] labeled in red. The bottom row shows the baseline-subtracted emission spectra from the two gray boxes, focusing on the rovibrational H₂O, SO₂, CH₄, and SiO features between 7.0–8.6 µm and the pure rotational lines of H₂O and OH between 18.5–21.5 µm.