Phys.org has reported:

Einstein’s theory predicts that matter falling into a black hole is compressed into a singularity, a point of infinite density where the theory breaks down. Most physicists expect quantum gravity to replace the singularity with a finite structure.

The black hole’s centre is hidden behind its horizon, raising the question of how researchers could learn what lies there. The source headline says three quantum-inspired cores leave opposite fingerprints on black hole ringing, but provides no further details about the cores or their effects.