Left panel: distribution of the 4FGL (Abdollahi et al. 2020) source types in the ABC source classes. Blue rectangles indicate BLLs, red rectangles indicate FSRQs, violet rectangles indicate BCUs, and white rectangles indicate other kind of sources (including compact steep spectrum radio sources, radio galaxies, starburst galaxies, generic active galactic nuclei, or unknown sources). Right panel: distribution of the WIBRaLS2 (D’Abrusco et al. 2019) source types in the ABC source classes. Blue rectangles indicate BZBs, red rectangles indicate BZQs and violet rectangles indicate MIXED sources.