Baku being quite concerned by privacy issues, the Sylphe infrastructure hosts a Firefox Sync instance. It is mostly used for personal purposes, however it might be opened for others to use later.
The Sync server runs behind Apache on
ffsync.sylphe.fr. However, user authentication still relies on Mozilla's Firefox Accounts service. HTTPS is enforced to avoid MITM attacks.
As data synced by Firefox Sync is in at least two locations (actually three for Baku), it is not backed yet.