Excerpted from the README file:

Term::Query.pm is a Perl 5 module, which performs generalized queries on
various kinds of values.  Validation and normalization of input, based
on the type, is automated, as is error reporting and re-solicitation of
input.

Input of '?', unless configured otherwise, provides useful, helpful
information, based on the expected input type, even in the absence of a
programmer-supplied help string.