Left: mixed-mode frequencies at different evolutionary stages along the RGB indicated in the right panel. Purple dots represent the individual frequencies of mixed modes, with the shade of the dots allowing to visualise the evolution of the mixed-mode order n_pg (the order is higher at high frequencies). Squares represent for each evolutionary stage the frequency of the ℓ = 1 g-dominated mode closest to ν_max (see Fig. 10 for the determination of this frequency). Middle: m = 1 magnetic splitting of ℓ = 1 mixed modes located inside [ν_max − 7Δν : ν_max + 7Δν] for each of the evolutionary stages denoted in the right panel. Squares represent for each evolutionary stage the frequency of the ℓ = 1 g-dominated mode closest to ν_max (ν_{1, g, max}, see Fig. 5) Right: Hertzsprung-Russell diagram of the M_⋆ = 1.5 M_⊙, Z = 0.02 star ascending the RGB. Coloured stars indicate the different evolutionary stages represented in the other panels.