Morpho

Synchronize is very similar to the Save action. I think the only difference right now is that you can invoke synch from the search/open dialog whereas a save requires you to open the package and then invoke save.
When you Save from Local>Network, the current id will be used unless it is already present on the network in which case an updated id will be used. This is the same for synch.
When you save from Network>Local, the network Id will be used locally unless it is already in use, in which case a new id will be generated and used. This is the same for synch.