I've collected a ton of books over the years, and I've noticed that whether interviews or Q&A PDFs are included as extras really depends on the publisher and the edition. Some special editions, especially collector's versions or anniversary releases, often bundle exclusive content like author interviews, behind-the-scenes insights, or even fan Q&A sessions. For example, I once got a limited edition of 'The Hobbit' that came with a digital download link for a PDF featuring Tolkien's early drafts and interviews about his writing process. It's not super common, but when it happens, it feels like striking gold. If you're specifically looking for this kind of content, I'd recommend checking the publisher's website or fan forums for details before buying.
Also, ebooks sometimes include these extras more frequently than physical copies. Platforms like Kindle or Kobo occasionally offer enhanced editions with bonus materials. I remember downloading 'The Silent Patient' and finding a PDF with psychological analysis interviews tucked in the extras section. It's worth digging into the product description or reviews to see if others mention it.