Application of GPR to the bolometric LCs of SN 1987A, SN 2009E, and OGLE-14 taken from the literature (see Ref. in Sect. 2.2) to identify the main LC features. The adopted GPR employs a constant mean function combined with a Matérn 3/2 kernel. For each SN LC, the key epochs t_m, ${\overline{t}}_{\mathrm{M}}$, and t_f^* are highlighted. The dashed line shows the luminosity contribution L_Ni due to ⁵⁶Ni–⁵⁶Co radioactive decay with M_Ni value reported within the panel of each SN.