RsyncOSX is a GUI on top of the command line utility rsync. Rsync is a file-based synchronization and backup tool. There is no custom solution for the backup archive. You can quit utilizing RsyncOSX (and rsync) at any time and still have access to all synchronized files. From version 6.4.6, RsyncOSX is compiled with support for macOS Catalina 10.15 and later versions.