What’s In An ODF File?
As you can see all four subdocuments as specified in the specification are present as well as several other files. In particular META-INF/manifest.xml list the contents of the package, including information such as full path and type.
This article is a good introduction to the XML files and other components found in a .odt word processing document file. For someone who is interested in creating applications that manipulate that format, this kind of knowledge is essential.