To view the upload history for a source of record, click on the “View upload history” menu item for the source of record.

This opens a table with all uploads of the chosen source of record. The table will show how many tags were in the upload, how many tags were added, how many edited and how many had no changes. 

To delve further, click on the “View upload details” menu item.

This will show all value changes for edited tags.