WP_List_Table::get_primary_column_name()

	protected function get_primary_column_name() {
		$columns = get_column_headers( $this->screen );
		$default = $this->get_default_primary_column_name();

		// If the primary column doesn't exist fall back to the
		// first non-checkbox column.
		if ( ! isset( $columns[ $default ] ) ) {
			$default = WP_List_Table::get_default_primary_column_name();
		}

		/**
		 * Filters the name of the primary column for the current list table.
		 *
		 * @since WP-4.3.0
		 *
		 * @param string $default Column name default for the specific list table, e.g. 'name'.
		 * @param string $context Screen ID for specific list table, e.g. 'plugins'.
		 */
		$column  = apply_filters( 'list_table_primary_column', $default, $this->screen->id );

		if ( empty( $column ) || ! isset( $columns[ $column ] ) ) {
			$column = $default;
		}

		return $column;
	}