  High-energy photons from cosmological emitters suffer attenuation due to pair
production interactions with the extragalactic background light (EBL). The
collective emission of any high-energy emitting cosmological population will
exhibit an absorption feature at the highest energies. We calculate this
absorption feature in the collective emission of blazars for various models of
the blazar gamma-ray luminosity function (GLF) and the EBL. We find that models
of the blazar GLF that predict higher relative contributions of high-redshift
blazars to the blazar collective spectrum result in emission that is more
susceptible to attenuation by the EBL, and hence result in more prominent
absorption features, allowing for better differentiation amongst EBL models. We
thus demonstrate that observations of such an absorption feature will contain
information regarding both the blazar GLF and the EBL, and we discuss tests for
EBL models and the blazar GLF that will become possible with upcoming Fermi
observations.
