Firefox Sync permits synchronize plugins, tabs, bookmarks, favorites, history over many Firefox instances.
In Firefox URL bar put: about:config
.
Search for: services.sync.tokenServerURI
.
Replace the URL by: https://mydomain.tld/path/token/1.0/sync/1.5
Create an account at Mozilla: https://accounts.firefox.com/signup
Install the plugin fxa-custom-server-addon
.