Let me clarify, it's my understanding that, the OP, @rusipka (and personally, myself), wants to see a list of tabs they have open in other devices that are on Safari (@rusipka please correct me if I misunderstood). This doesn't have to be 'iCloud Sync' but it will indeed provide the requested functionality so that the user can see their tabs on (all) Safari instances (iPhone, iPad, Macs, etc..). An app that provides this functionality already exists;
https://github.com/josh-/CloudyTabs
It would be trivial to add this to Orion, where the tabs are shown (as read-only), under the Windows Menu. The tabs are conveniently stored in SQLite database. As for the update of the list, I am not sure if it's updated via Safari or as a service but I would assume it would be part of SafariCloudHistoryPushAgent, if that is the case, there is table called CloseRequests which means you can actually implement the whole functionality.