If you're lucky enough to succeed in creating an expansive, in-depth world of your own that exists in secret behind the real one, pretty quickly, you're bound to get asked questions about it. As popularity grows, fans will inevitably want to dig deeper, and critics are going to love finding holes that haven't been plugged or stones that haven't been looked under.
Sites all across the Internet contain lists of questions that fans are determined to have answered. Heroes are formed when fans think they've come up with a truly original query or possible criticism. Videos are made listing all of the inconsistencies or ideas that simply don't add up or quite make sense. It's part and parcel of world building.
In most cases, those questions either go unanswered or merely speculated at by other fans, which offers compelling insight, but is never quite as satisfying as something more definitive. But luckily, in the Wizarding World, the voice of the creator is loud and generous, as JK Rowling has revealed a lot about her most famous creations well after publication.
And even when she's sick of the questions, she's still answered them...