[K/Mg] (upper panel) and [Sc/Mg] (lower panel) versus the initial metallicity. The adopted solar reference is from Asplund et al. (2009). The different colored labels identify each set of models (see bottom legend): RAU Rauscher et al. (2002); NOM Nomoto et al. (2013); RIT Ritter et al. (2018a); L&C Limongi & Chieffi (2018); PUSH Ebinger et al. (2020); ROB Roberti et al. (2024b); RLC Roberti et al. (2024a); KEP Jeena et al. (2024). Different symbols identify different initial masses (see top legend). Models with and without a C-O shell merger are represented by a filled and an empty symbol, respectively.