The SIR DR1-Foundation data processing is derived from the Q1 processing, described in Euclid Quick Data Release (Q1) - From spectrograms to spectra: the SIR spectroscopic Processing Function. The numerous upgrades of the SIR pipeline are described in Euclid Data Release 1 (DR1). From spectrograms to spectra: The SIR spectroscopic processing function. The calibration used by the SIR PF are described in Euclid Data Release 1 (DR1). SIR spectroscopic calibration.