How do users know when TL data has been extracted

Summary:

We're creating a custom TL extract to pull time record data to send to a third party.

Content (required):

From the front end user interface, how can a user determine which time card records have already been "extracted" and sent to the third party for internal tracking purposes? I understand that we can create a changes only extract so that the extract will know where it left off but can a user tell by looking at the data or a report to see which data has already been extracted and sent to the third party?

Thanks

Version (include the version you are using, if applicable):