LibreSource support Subversion by providing an automatic way to create a subversion repository and by managing its security.
Its a resource on its own like the LibreSource synchronizer. A LibreSource Synchronizer can't be accessed with a subversion client.
To access, to the services provided on subversion, you will have to install LibreSource with a subversion server and configure both in order to allow each other to work together.
This information is available in the install file provided in the source package.
Regards,
Seb