Right now the SVNPubSub server serves NUL separated JSON data as text/plain. This is clearly wrong. But application/json would be just as wrong. I'd prefer that we use something more specific than application/octet-stream.
On IRC we've been discussing applying for a vendor tree media-type registration with IANA. After discussion Daniel and I agreed to: application/vnd.apache-subversion.pubsub-stream+json We're envisioning the following pattern for Apache projects (and assuming there's no objections within the svn-dev community will propose it to operations@): vnd.apache-${project}.${format} and vnd.apache.${format} The latter one would be used for cross project formats.