While using Time Machine on a Macintosh you find a lot of files fill up the internal hard drive space and cannot be deleted. The same can happen from a USB drive being ejected before DLP is able to scan the files.
DLP needs to process the files being copied. If DLP does not have time to process, DLP copies the files to this frbackup folder for process.
System Integrity Properties (SIP) may be turned on. Time Machine, external hard drive, or a USB drive may be in use.