The DRM_LicenseID property contains a string retrieved from the license associated with the currently open file that uniquely identifies that license.
The license ID is stored in a license, not in an ASF file. Each individual license has a unique ID which is assigned by the license generator at the time the license is created. For example, if you obtain two licenses for the same content, each one will have a different LicenseID attribute. Typically, applications have no need to retrieve this value.