Salesforce to Salesforce Sync Status & Rec Detail by Yasir Arafat

Salesforce to Salesforce Sync Status & Record Details plugin works in both Classic and Lightning:
i) Shows Salesforce to Salesforce record Sync Status and corresponding Partner Id of the shared record in the target Org

ii) Shows all Field values for the given record and it's complete Field History

iii) UUID/GUID Converter

It's also available for Chrome: https://chrome.google.com/webstore/detail/salesforce-to-salesforce/amjffmpjihnjbfpnkkdpfkbaiogbeong