VLT/MUSE mean stacked spectra of 9, 22, and 8 cluster member galaxies of SDSS J1029+2623 (top, z = 0.59), MACS 1149 (middle, z = 0.54), and SDSS J2222+2745 (bottom, z = 0.49), respectively, with σ_⋆ > 180 km s⁻¹. The shaded regions are the standard deviation of each spectral pixel. The spectra are smoothed by applying a Gaussian kernel with a standard deviation of 3.75 Å. For a clear visualisation, the flux values of MACS 1149 and SDSS J1029+2623 have been increased by 1 and 2, respectively. The red dashed vertical lines locate the absorption features detected in the spectra, while the blue lines mark the expected positions of emission lines characteristic of young, star-forming populations. The green dashed lines denote the Fe and Mg lines typically used to estimate the stellar metallicity of the population. We note that the strong residual emissions observed at 4800 Å and 5100 Å for SDSS J1029+2623 and SDSS J2222+2745, respectively, are due to an incomplete subtraction of sky lines.