Left panel: Frequency separation ratios (r₀₁) of KIC6679371 as a function of observed frequency. Right panel: Surface lithium abundance as a function of normalised central hydrogen abundance. The observed value, associated with the X/X₀ from the optimal model, is shown in red. The green, orange, and blue diamonds indicate the positions of Models 1, 2, and 3. Three evolutionary models at the end of the main sequence (denoted Models 1, 2, and 3) are shown.