Selection of representative spectra (log10 flux) of a few given regions. Top: full observed spectrum over a bright region in the core of the nebula (area 1 arcsec² − 25 MUSE spaxels) centred at (Δα − 5.2″, Δδ + 6.4″) relative to the position of the CS. Bottom: three example spectra over freckles chosen to sample faint, average, and bright freckles (based on their extracted Hα and [N II] fluxes; see Sect. 5.2). Left: spectrum of a faint freckle (9). Centre: Spectrum of a freckle (12) whose Hα and N II fluxes mark it as of average brightness; spectrum of the brightest freckle (94). Note: these spectra of freckles include the (high-ionisation) background nebular spectrum within the area of the freckle.