This table lists the sources in the catalogue with uncertain redshift information, ordered by their |$\tau _{(E,z)}$| values calculated at |$E^{\rm{bin}}_{\rm{max}}$|⁠. The first three columns show the source names, RA, and Dec. in degrees (J2000), respectively. The fourth column presents redshift information from the literature, with a ‘(?)’ flag indicating uncertain or photometric values and a ‘>’ symbol denoting lower limits. The ‘z-origin’ column specifies the literature reference for the redshift, using the short names described in Section 3.1. The ‘b (deg)’ column shows the galactic latitude in degrees, followed by the associated ‘4FGL-DR4’ name. The ‘TS’ column provides the test statistic value derived for 1CGH sources detected above 10 GeV, integrating over 16 yr of Fermi-LAT observations. The columns ‘|$E_{\mathrm{ max}}^{\mathrm{ bin}}$|’ and ‘|$\rm \tau _{Ebin}$|’ list the largest energy bin detected and the corresponding EBL optical depth |$\tau _{(E,z)}$|⁠, respectively. For sources whose ‘Name’ begins with 4FGLJ, the RA and Dec. correspond to the associated counterpart position (see the ‘ASSOC1-4FGL’ column in Ballet et al. 2023).