BackupCompleteFilename is a filename, which is created in the destination fs when backup is complete.

BackupMetadataFilename is a filename, which contains metadata for the backup.

ProtectMarkFileName is the filename for "protection mark" file.

RestoreInProgressFilename is the filename for "restore in progress" file This file is created at the beginning of the restore process and is deleted at the end of the restore process.

RestoreMarkFileName is the filename for "restore mark" file.