Central specific entropy, s_c, as a function of CO core mass, M_CO, at core collapse for the single-star and Case A and B accretor models. The Case C accretors are not shown to enhance the clarity of the diagram. The entropy peak at M_CO ≈ 6 − 8 M_⊙ associated with BH formation is indicated by the yellow box. Colours relate the models to their pre-SN location in the HR diagram and hence their likely appearance as SN IIn, SN IIP, and SN 1987A-like. The horizontal and vertical black dotted lines help to visually distinguish between the different SN groups and the typical central entropies that models in these groups have at core collapse. The black crosses indicate models that likely experience significant LBV-like mass loss, and grey boxes show cases of likely SN fallback.