  Quantum considerations have led many theorists to believe that classical
black hole physics is modified not just deep inside black holes but at {\it
horizon scales}, or even further outward. The near-horizon regime has just
begun to be observationally probed for astrophysical black holes -- both by
LIGO, and by the Event Horizon Telescope. This suggests exciting prospects for
observational constraints on or discovery of new quantum black hole structure.
This paper overviews arguments for certain such structure and these prospects.
