MUSE galaxy spectra matrix in the rest frame. This matrix shows selected MUSE galaxy spectra, prepared for NMF decomposition. Spectra are sorted by increasing redshift (from bottom to top) and transformed to their rest frame. Key redshifts are shown on the y-axis and important spectral lines are indicated on top of the figure. The color of each pixel encodes flux density, scaled using a 95% z-scale to enhance the visibility of emission lines. Bluer colors represent higher flux densities; white pixels denote missing or unobserved data.