If you want to export a copy of your location external keys simply go to 'Locations' and hit the "export" button in the top right of the screen.
Next click on Excel (All) and you will be emailed an Excel spreadsheet containing a list of your locations.
From your email, the spreadsheet will look like this:
This will show you all location information including external keys, tags, and hierarchy related information.
If you have any further questions or concerns please feel free to reach out to firstname.lastname@example.org.