Retrospect
From Just Solve the File Format Problem
Retrospect is Client-Server backup software[1] capable of incremental backups to Hard Drive, Tape, Optical disc and more. Originally developed by Dantz for the Macintosh in the late 1980's, but now runs on most platforms.[2]
Retrospect backup software creates a catalog index of all backups and stores them in a single file with a RBC or RBF extension.
File Identification
Rectrospect catalog files begin with the hex values 2E686643
or 4366682E
depending on endianness.