Can you please also include in the 'Firefox Syncing' the Exceptions lists and settings in the 'Privacy and Security' section of Settings in the Desktop version?

This would be the exception list for: History: allowed/blocked cookies; Forms & Passwords: Logins Exceptions; Tracking Protection: Exceptions; Pop-up windows Exceptions; Website's add-ons warning Exceptions. Also, include the syncing of the 'One-click Search Engines' list.