What does robocopy mean by tweaked, lonely and extra?

Question

The robocopy documentation for the option /it is simply Includes "tweaked" files. What does tweaked mean?

The robocopy documentation for the option /xl is simply Excludes "lonely" files and directories. What does lonely mean?

Answer 1

"Tweaked":

A Tweaked file is defined to be one that exists in both the source and destination, with identical size and timestamp, but different attribute settings.

"Lonely":

A "lonely" file is present in source but not destination; excluding lonely will prevent any new files being added to the destination.

"Extra" (the other one that isn't explained well):

An "extra" file is present in destination but not source; excluding extras will prevent any deletions from the destination.

More info here.