The targets is each type of change that can be made. While the type of action is one of: Update, Install, Create or Delete. The specific days wanted can also be specified in the starting and ending dates. Itll show all the changes between those days.
Clicking on the "view details" button for any change will give a bit more information. For example if the change was adding a manager, the person who was added will be shown. Or if the change was a visibility change, it would show what the visibility was before.