Fifteen RPs from the k-means clustering of the Hβ line that are identified as a signature of QSEB. The black lines show RPs, and shaded colored areas represent the density distribution of Hβ spectra within a cluster. Darker shades indicate a higher density. Within a particular cluster, the Hβ profile that is farthest (measured in Euclidean distance) from the corresponding RPs is shown by the dotted black line. As reference, the average quiet-Sun profile (gray line) is plotted in each panel. RPs 0–9 (blue) show the typical EB-like Hβ profiles, i.e., significantly enhanced wings and an unaffected line core, while RPs 10–12 (green) display weak enhancement in the wings. RPs 13 and 14 (red) show intensity enhancement in the line core. The differentiation into three groups of QSEB clusters is similar as in Paper II. The parameter n represents the number of spectral profiles in a cluster as the percentage of the total of ∼1.7 × 10⁹ spectra.