Example of the fits to the spectral features used as mixing indicators in the case of HD 175679. The solid red line is the best-fitting synthetic profile, while the two dashed lines show the profiles for an abundance deviating by ±0.1 dex (and deviating by Δ¹²C/¹³C= 5 in the case of ¹³CN 8004.7). The blue, dotted lines show the profiles for no Li present (Li i λ6708) and solar abundance ratios with respect to iron for the CNO features. In the case of ¹³CN 8004.7, the magenta and dark green lines show the profiles for ¹²C/¹³C= 89.4 and 3.5, which correspond to the terrestrial and CNO-equilibrium values, respectively.