From Confluence 5.5 we plan to stop providing XML exports of the complete Confluence documentation.
The documentation has grown very large and contains content drawn from a number of other spaces for features that are shared between products (for example user management, application links, the universal plugin manager and more). This has made for a poor experience for users accessing the documentation locally (from an export that has been imported into their Confluence instance).
We will continue to provide PDF exports of the documentation for all major versions of Confluence.
If you have concerns or comments on this decision, please feel free to comment on this ticket.