Observed abundances of HE 1327 and observational upper limits (black) together with the yield abundances from different stellar models. Upper panels: Results from 1 M_⊙ models undergoing PIEs. Lower panels: Results from massive star models undergoing SN explosions. The Z = 10⁻⁸ model (upper left) is from Cruz et al. (2013). The [Fe/H] = −5.76 (upper right) is from Campbell et al. (2010). The yields from Ezzeddine et al. (2019, lower-left panel) are from a primordial 25 M_⊙ star undergoing an asymmetric mixing and fallback SN explosion. The yields from Jeena et al. (2023, lower-right panel) correspond to a rapidly rotating 12 M_⊙ star of Z = 0 undergoing very efficient mixing and quasi-chemically homogeneous evolution prior to a SN explosion. The grey-shaded areas highlight the elements for which no theoretical abundances were reported. Note that in the model by Jeena et al. 2023, the authors did not consider the C and N abundances separately but instead summed them and plotted the resulting value at the location of C. We added the grey bar at the location of N to note this. As in Fig. 2, error bars are 2σ, and the shading has the same meaning. We present two determinations for O (solid circle from Ezzeddine et al. 2019 and open circle from Frebel et al. 2006) to illustrate the measurement uncertainty for this element. Observed abundances are compiled from the literature; most are from Table 1 in Ezzeddine et al. 2019, which incorporates the 3D values from Frebel et al. 2008. Abundances for Si and Fe are from Ezzeddine & Frebel 2018. The upper limit for S is from Bonifacio et al. (2012), and V and Cr from Frebel et al. (2008). Lower panel: Residuals from the comparison. The χ² values are given in Table A.1.