What is “beneficial ownership” and what does it mean for our NPO?

I’ve been reading through some of the new requirements for NPOs and I keep coming across the term ‘beneficial ownership’ and I genuinely don’t understand what it means in our context. I get what it means for a regular business but for a non-profit it seems different. Is it just about who’s on the board? Do we need to file something separately for this, or is it already captured in our existing registration documents? We have three directors and I want to make sure we’re doing whatever we’re supposed to be doing.