What is the purpose of Sidebery "sync", and how to use it?

[wsalopek]

Does "sync" automatically send/receive data to/from two different computers, or the cloud, etc? It doesn't look like it, but if it's not syncing with another device/cloud, what does syncing actually do?

[mbnuqw]

Sync uploads selected data to Firefox sync-server (via sync API) and on another profile it loads that data, so you can manually check what data you have, from what device and use the needed.