$ perlcritic --verbose 11 foo.pl
"require" statement with library name as string at line 6, near 'require '/tmp/config.pl';'.
  Modules::RequireBarewordIncludes (Severity: 5)
    When including another module (or library) via the `require' or `use'
    statements, it is best to identify the module (or library) using a
    bareword rather than an explicit path. This is because paths are usually
    not portable from one machine to another. Also, Perl automatically
    assumes that the filename ends in '.pm' when the library is expressed as
    a bareword. So as a side-effect, this Policy encourages people to write
    '*.pm' modules instead of the old-school '*.pl' libraries.

        use 'My/Perl/Module.pm';  #not ok
        use My::Perl::Module;     #ok

##</code><code>##

require '/tmp/config.pl'; ## no critic (RequireBarewordIncludes)