Today, I was just checking how much free disk space I had, and went to Apple, About this Mac, More info, and Storage. I was surprised there was a section called "Backups." I usually backup with an external HDD, so this was a complete surprise for me. Thinking that this was some kind of a feature, I clicked on the "Enter Time Machine" without connecting my external HDD, and there it was, a Time Machine backup inside my HDD!? I have no idea what's going on. It's been backing it up every hour. Is this normal?