Evolutionary tracks of model stars of metallicity Z = 8 × 10⁻³ on the (J − K, J) colour-magnitude diagram. The different points along the tracks refer to some selected evolutionary stages taken during the AGB phase, chosen in order to well represent the excursion of the tracks on the observational plane. The grey shaded region indicate the box chosen by Magnus et al. (2024) for the J region. The masses given for M <  1.5 M_⊙ refer to the values attained at the TRGB.