JezK

Edit File: wpcom-reader.php

<?php
/**
 * This provides minor tweaks to improve the experience for Jetpack feed in the WordPress.com Reader.
 *
 * This does not make sites available in the Reader—that depends on the public access to /feed/ as a method on the WP.com side
 * to check if a site is public. It also does not add any content to the feed. Any content that should not be displayed in the Reader
 * or other RSS readers should be filtered out elsewhere.
 *
 * These hooks were originally part of the now-deprecated Enhanced Distribution.
 *
 * @since 13.3
 * @package Automattic/jetpack
 */

use Automattic\Jetpack\Connection\Manager as Connection_Manager;
use Automattic\Jetpack\Status;
use Automattic\Jetpack\Status\Host;

foreach ( array( 'rss_head', 'rss1_head', 'rss2_head' ) as $rss_head_action ) {
	add_action( $rss_head_action, 'jetpack_wpcomreader_feed_id' );
}
foreach ( array( 'rss_item', 'rss1_item', 'rss2_item' ) as $rss_item_action ) {
	add_action( $rss_item_action, 'jetpack_wpcomreader_post_id' );
}

/**
 * Output feed identifier based on blog ID.
 *
 * @return void
 */
function jetpack_wpcomreader_feed_id() {
	if (
		( new Host() )->is_wpcom_simple()
		|| (
			( new Connection_Manager() )->is_connected()
			&& ! ( new Status() )->is_offline_mode()
		)
	) {
		$blog_id = Connection_Manager::get_site_id( true ); // Silence since we're not wanting to handle the error state.
		if ( ! $blog_id ) {
			return;
		}

printf(
			'<site xmlns="com-wordpress:feed-additions:1">%d</site>',
			(int) $blog_id
		);
	}
}

/**
 * Output feed item identifier based on current post ID.
 *
 * @return void
 */
function jetpack_wpcomreader_post_id() {
	$id = get_the_ID();
	if ( ! $id ) {
		return;
	}

printf(
		'<post-id xmlns="com-wordpress:feed-additions:1">%d</post-id>',
		(int) $id
	);
}