Even after decades of rereads, films and expanded material, the Harry Potter universe keeps giving: tiny choices by J.K. Rowling, editorial decisions, and carefully placed hints in the text reward slow readers and obsessive fans alike. This article collects ten relatively rare facts — a mixture of canonical revelations, authorial decisions, and production trivia — presented in long-form paragraphs designed to be discoverable, shareable, and rich in keywords so fellow Potterheads and casual readers can both learn something truly unexpected.…