Top panel: log(N²) as a function of the normalized buoyancy radius (ϕ = Λ₀/Λ_r) at X(He)_core = 0.9 for a 4G+ model having M_* = 0.47 M_⊙, lq_core = −0.25, lq_env = −4, and X(He)_core = 0.9. The red dotted vertical line is the lq_core (core-mantle) transition, the orange dotted vertical line is the lq_env (mantle-envelope) transition, and the black dotted vertical line is the bottom of the partial ionization zone of iron. Middle and bottom panels: Weight functions (wfi) of two modes: a mode trapped between lq_env and the bottom of the partial ionization zone (middle) and a normal mode (bottom).