R23–O32 diagram, probing the ionisation and excitation of the ISM. The JADES sub-samples at z ∼ 6 (purple points) and z ∼ 8 (maroon points) lie at generally high excitation an high ionisation. Comparison samples, including SDSS, MOSDEF, green peas, blueberries, and SMACS 0723, are shown as in Fig. 4. z ∼ 4.5 − 8 galaxies from GLASS are shown as grey diamond (Mascia et al. 2023). Blue and orange open circles show the z ∼ 5.6 and z ∼ 7.5 composite CEERS spectra from Sanders et al. (2023), while the z ∼ 7.7 composite CEERS spectrum from Tang et al. (2023) is shown as the green open hexagon. Stacked JADES spectra are shown as the open magenta and red diamonds.