The package defines a single command \verbdef (which has a *-
form, like \verb). \verbdef will define a robust command whose
body expands to verbatim text. By using commands defined by
\verbdef, one can put verbatim text into the arguments of
commands; since the defined command is robust, it doesn't
matter if the argument is moving. (Full details of syntax and
caveats about use are in comments in the file itself.)