There may exist a use-case to export the licenses from an API Gateway through tools like GMU or the database directly in order to extract a copy of the license.
This article applies to all versions of the API Gateway.
There is currently no supported manner of extracting a license from an existing/licensed system. If a license file is simply lost, then the Broadcom Support number should be called and they can re-send the relevant active licenses as needed.
The call numbers are located on this page: https://www.broadcom.com/support/services-support/ca-support/contact-support