pcomplete-help

pcomplete-help is a variable defined in `pcomplete.el'.
Its value is

nil

Documentation:
A string or function (or nil) used for context-sensitive help.
If a string, it should name an Info node that will be jumped to.
If non-nil, it must a sexp that will be evaluated, and whose
result will be shown in the minibuffer.
If nil, the function `pcomplete-man-function' will be called with the
current command argument.

You can customize this variable.