Thanks, but then which servers does it use? Separate ones, really?
Then when is it enabled: If you as a user enable Firefox Sync and enable syncing of “add-ons”, I guess, is not it?
Note these question likely matter for what you, as an add-on dev, write in your privacy policy. Currently I write e.g. that the data there is synced via Firefox Sync and also link to Mozilla’s privacy policy for Firefox Sync.
Seeing you reply, this does not seem to be really wrong. Am I right that the “frontend” for the user is basically Firefox Sync? (but there are just separate backend servers used)