When you create a new Property List, the created file looks like this:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict/>
</plist>
When you open this file within Xcode's designated editor, it shows you an empty document with a "Root" Dictionary. It's a smart editor :) and it all starts with that "Root".