Here it is:
A black hole firewall is a hypothetical phenomenon where an observer falling into ablack hole encounters high-energy quanta at (or near) the event horizon. … The use of a firewall to resolve this inconsistency remains controversial, with high-energy physicists divided as to the solution to the paradox.
Primordial black holes are non-baryonic and as such are plausible dark matter candidates. Primordial black holes are also good candidates for being the seeds of the supermassive black holes at the center of massive galaxies, as well as of intermediate-mass black holes.
Firewall