Distribution of post-MS primaries in the HR diagram (the vast majority being at the core-He burning stage) inferred from the grid of q = 0.6 binary models at the LMC composition. For the SMC version of this figure see Fig. A.5. Models have been weighted by the initial mass function and orbital period distribution of early-type binaries, and normalized to a constant star formation rate of 1 M_⊙ yr⁻¹ (see text). The overall distribution is showed in grayscale. In addition, we plot a random sampling of stars from the distribution, color-coded according to their pre- or postinteraction state. Several single stellar tracks are plotted with solid lines for comparison. Around 30% of primaries reside in wide noninteracting systems. The four Boxes indicate four characteristic regions: hot stripped stars from both case A + case AB evolution as well as those formed through case B mass transfer (Box I), hot stripped stars from case A + case AB mass transfer only (Box II), a region where most of the stars are donors in currently mass-transferring systems (Box III), and finally a region where most of the long-lived partially stripped stars in detached binaries reside (Box IV).