> Since the Mozilla-hosted sync servers will not trust assertions issued by third-party accounts servers, you will also need to run your own sync-1.5 server.
The tutorial refers to the old unmaintained version: https://github.com/mozilla-services/syncserver, see https://github.com/mozilla-services/syncserver/commit/8d9804...
The alternative is https://github.com/mozilla-services/syncstorage-rs which is ridiculously hard to set up.