The /MIR parameter
Mirroring the Source directory in the Destination directory.

Mictosoft's RichCopy knows the /P parameter to purge(delete) files form the Destination directory, when they no longer exist in the Source directory.
Confusing to many, it purges the files but not the directories in the destination, leaving those behind as an empty directory instead.

To make the Destination directory a full 'mirror' of the Source directory, RichCopyPlus introduces the /MIR parameter.
This deletes the orphaned files (those without an equivalent in the Source directory) from the Destination directory as well as the directories that are orphaned, instead of leaving them behind as empty directories.