[JimmyR]

Originally Posted by HarryT

But my point still stands: that the file extension will vary depending where you got the book from, and doesn't reliably indicate the format. A file with an extension of ".AZW" may be either an old "MOBI7" or a newer "KF8"-format file, depending where it came from.

Thanks. I never knew that about Kindle for PC—never really used it much. But yes, you are correct. Every single book I downloaded to it was an AZW. Some were old mobi7, some KF8—with and without DRM.