pear info XXX where XXX is a valid, installed package (or .tgz, etc.) does a whole bunch of array to string conversion because there is no handler for the Provides section.  I would suggest only listing classes, as in this code:

                    case 'provides' : {
                        // only list provided classes
                        $result = 'Classes: ';
                        foreach($info[$key] as $program_element) {
                            if ($program_element['type'] == 'class') {
                                if ($result != 'Classes: ') {
                                    $result .= ', ';
                                }
                                $result .= $program_element['name'];
                            }
                        }
                        $info[$key] = $result;
                        break;
                    }