What should a user know about how HN moderation works in practice?

It seems I am in some kind of shadow ban, but I just realized it. I am not even sure it's the case, when it started or what was the reason. Never got a hint it could happen. Is there some process to get out of the purgatory, or to check what caused it, or even only a way to confirm it's effectively the case ?

I am asking here just to understand from others experience. And I am just wanting to know what I should know, nothing more ( I don't think it warrants more than that).