kartik\export\ExportMenu::getColumnLabel PHP Method

    protected function getColumnLabel($key, $column)
    {
        $label = Yii::t('kvexport', 'Column') . ' ' . ($key + 1);
        if (!empty($column->label)) {
            $label = $column->label;
        } elseif (!empty($column->header)) {
            $label = $column->header;
        } elseif (!empty($column->attribute)) {
            $label = $this->getAttributeLabel($column->attribute);
        } elseif (!$column instanceof DataColumn) {
            $class = explode("\\", $column::classname());
            $label = Inflector::camel2words(end($class));
        }
        return trim(strip_tags(str_replace(['<br>', '<br/>'], ' ', $label)));
    }