Free users don't have access to downloadable backups, but you still have ways to get your data out of ProjectLocker if you wish to move to another provider or simply to archive your data.
svnrdump dump [PROJECTLOCKER URL] > output_file.dump
to get the full contents of your repository. These can be imported to any Subversion server.
Git takes a full copy of the repository, so cloning all branches should be sufficient.
We don't provide a dump of Trac for free accounts, but you can access your data using the Trac XML-RPC API. Examples for multiple languages are available at: