Gather's history of changes allows you to view all changes to an item from the moment it is added to a project.
An item's change history can be found by opening an item and clicking on the "History" tab within the menus on the left side of an item.
To search for a specific change, you can use the filter options to find what you're looking for quickly.
To start a new search, click "reset filters" in the lower right corner of the filter box.