Corner plot showing a small selection of the asteroseismic inferences, all with the same Gaussian observational constraints highlighted by the full lines, ± the dotted lines indicating the 1σ level uncertainty on surface metal fraction, effective temperature, and frequency of maximum power. The grey MESA fit samples initial helium fraction as a free parameter. The lower bound on helium fraction is 0.248. The asteroseismic frequency constraints employed were KEPSEISMIC+PBJam (see Sect. 2.6.1 for description).