/**
	 * Retrieve the header row for generating an export file
	 *
	 * @since 3.15.0
	 * @since 3.17.3 Fixed SYLK warning generated when importing into Excel.
	 *
	 * @return array
	 */
	public function get_export_header() {

		$cols = wp_list_pluck( $this->get_columns( 'export' ), 'title' );

		/**
		 * If the first column is "ID" force it to lowercase
		 * to prevent Excel from attempting to interpret the .csv as SYLK
		 *
		 * @see https://github.com/gocodebox/lifterlms/issues/397
		 */
		foreach ( $cols as &$title ) {
			if ( 'id' === strtolower( $title ) ) {
				$title = strtolower( $title );
			}
			break;
		}

		/**
		 * Customize the export file header columns.
		 *