Block/System/Config/Form/Field/Acl.php
protected function _construct() // @codingStandardsIgnoreLine - required by parent class
    {
        $this->addColumn('backend_name', ['label' => __('Name')]);
        $this->_addAfter = false;
        $this->_template = 'Fastly_Cdn::system/config/form/field/acl.phtml';

        parent::_construct();
    }
protected function _construct() // @codingStandardsIgnoreLine - required by parent class
    {
        $this->addColumn('backend_name', ['label' => __('Name')]);
        $this->_addAfter = false;
        $this->_template = 'Fastly_Cdn::system/config/form/field/acl.phtml';

        parent::_construct();
    }
Initialise form fields

@return void