Source

File: wp-admin/includes/class-wp-list-table.php

public function get_pagination_arg( $key ) {
		if ( 'page' === $key ) {
			return $this->get_pagenum();
		}

		if ( isset( $this->_pagination_args[ $key ] ) ) {
			return $this->_pagination_args[ $key ];
		}
	}