  Non-thermal magnetospheric processes in the vicinity of supermassive black
holes have attracted particular attention in recent times. Gap-type particle
acceleration accompanied by curvature and Inverse Compton radiation could in
principle lead to variable gamma-ray emission that may be detectable with
current instruments. We shortly comment on the occurrence of magnetospheric
gaps and the realisation of different potentials. The detection of rapid
variability becomes most instructive by imposing a constraint on possible gap
sizes, thereby limiting extractable gap powers and allowing to assess the
plausibility of a magnetospheric origin. The relevance of this is discussed for
the radio galaxies Cen A, M87 and IC310. The detection of magnetospheric
gamma-ray emission generally allows for a sensitive probe of the
near-black-hole region and is thus of prime interest for advancing our
understanding of the (astro)physics of extreme environments
