https://docs.cloud.google.com/appengine/docs/standard/python3/reference/services/bundled/google/appengine/ext/blobstore/BlobMigrationRecord
google.appengine.ext.blobstore.BlobMigrationRecord | App Engine standard environment | Google Cloud...
Defines a model that records the result of a blob migration.
google appenginestandard environmentextblobstoreblobmigrationrecord