Mean age and metallicity for UDG11 derived from the stacked spectrum inside 1R_e. Left panel: best fit derived using the pPXF code. The red cross corresponds to the values for age and metallicity (including errors) obtained by the best fit on the whole MUSE spectral range. The orange cross shows the average age and metallicity (including errors) for one of the confirmed GCs in UDG11 (see Sect. 5.5). Right panel: lick index measurements. Using the E-MILES BaSTI templates, we constructed the grid: vertical dashed lines denote models for the same age (left being the oldest), and horizontal dotted lines refer to model measurements for spectra with the same metallicity (with the most metal-poor ones located at the lower part).