Now that you understand how "require" looks for files in the
            case of a bareword argument, there is a little extra
            functionality going on behind the scenes. Before "require" looks
            for a ".pm" extension, it will first look for a filename with a
            ".pmc" extension. A file with this extension is assumed to be
            Perl bytecode generated by B::Bytecode. If this file is found,
            and it's modification time is newer than a coinciding ".pm"
            non-compiled file, it will be loaded in place of that
            non-compiled file ending in a ".pm" extension.