N/O abundance ratio as a function of O/H from the sample of 2212 low-z compact star-forming galaxies from Izotov et al. (2021) with [O III]λ4363 detections. N/O was determined from the [N II] λλ6584/[O II] λ3727 ratio using the recent calibration from Cataldi et al. (2025) for low-z galaxies. The solid line shows their mean relation at low-z, the dash-dotted line that from Vila-Costas & Edmunds (1993). The figure illustrates the absence of low-z objects with very high N/O abundances ($log(\mathrm{N}/\mathrm{O})\gtrsim -0.8$), comparable to those of the objects classified as N-emitters in Morel et al. (2025) and this work.