STIX spectra for the same events shown in Fig. 1. The solid black line illustrates the observed, background-subtracted flare spectra, while the dashed black lines display the background. The thermal and nonthermal models are represented by the red and blue curves, respectively. The sum of the two models is shown as a gray line. Beneath each spectrum, the residuals are provided, which are calculated by subtracting the total fit from the data and normalizing the result by the error bar.