Voluntary sharing, since afaik they don't pay the criminals to get the data. Either the criminals share it directly (fat chance, usually), or someone else bought it and shared it either publicly, privately with HIBP, or privately with someone who then reported it to HIBP
How this specific instance unfolded, time will have to tell. The leak may have occurred in 2020 for all we know at this point
How this specific instance unfolded, time will have to tell. The leak may have occurred in 2020 for all we know at this point