Rest-frame C III] λ1909 (left panel) and C IV λ1550 (right panel) EWs as a function of metallicity O/H for the LyC emitters (large red squares: strong leakers, f_esc >  0.1; blue circles: other leakers) and low-z comparison samples from the literature taken from the compilation of Schmidt et al. (2021). All measurements are for galaxies with direct metallicity measurements. The typical relative errors for our sources are 10−20% for all EW(C III]) and for EW(C IV) ≳ 5 Å, and larger otherwise (shown).