Composition structure at core helium depletion for a subset of the single (top) and binary-stripped star (bottom) grids. Below each set, we indicate the initial masses of these models. Single (S₁ and S₂) and binary-stripped star (B₁ and B₂) models with similar reference core masses are highlighted with the same gray background color. Dashed yellow circles indicate the edge of the helium-depleted core. Outside the helium-depleted core, binary-stripped star models contain a layer that consists of a gradient of ¹²C, ¹⁶O, and ²⁰Ne, whose extent increases with an increasing helium core mass. This layer is not present in single-star models. The neon isotope would be ²²Ne in reality and is only ²⁰Ne as an artifact of the approx21 network.