Optical spectra of the I20210 components. Top panel: I20210N. Middle panel: I20210S. Bottom panel: the spatially extended South Nebula. In all panels: (i) the detected signal is reported along with its rms uncertainty (cyan bands); (ii) the zero-flux level (dashed line) is indicated; and (iii) the positions of major emission (top) and absorption features (bottom) are labeled accordingly.