I made an incorrect assumption with the "keep existing" feature. jkeys should not be kept if a file in the key exists. All old jkeys should be deleted to honor the max_age flag. However there are times when that would mean that all listdir.json files are deleted, making it impossible to restore without manually creating the file. So the compromise when using the "keep existing" feature is to always keep at least one jkey (listdir.json file).
I made an incorrect assumption with the "keep existing" feature. jkeys should not be kept if a file in the key exists. All old jkeys should be deleted to honor the max_age flag. However there are times when that would mean that all listdir.json files are deleted, making it impossible to restore without manually creating the file. So the compromise when using the "keep existing" feature is to always keep at least one jkey (listdir.json file).