The external file in the example fetch.txt file is not present in the payload manifest files. This was always a requirement of the 0.97 BagIt spec, and is more explicit in the 1.0 version: "Every file listed in the fetch file MUST be listed in every payload manifest" (https://tools.ietf.org/html/draft-kunze-bagit-17#section-2.2.3)
The external file in the example fetch.txt file is not present in the payload manifest files. This was always a requirement of the 0.97 BagIt spec, and is more explicit in the 1.0 version: "Every file listed in the fetch file MUST be listed in every payload manifest" (https://tools.ietf.org/html/draft-kunze-bagit-17#section-2.2.3)