Thanks for compiling/copying the information out of Changelog June 30, 2016.
Unfortunately your Text is partly wrong, probably through using outdated information or misinterpretation.
Those features are mostly optional and the optional Sync uses Firefox sync as for the storage.sync API. (This Addon Version is currently only maintained for Firefox Browser) You are also welcome to have a in depth look at the actual source code provided on github and as linked on this page for future references.