Remove Missing Attachment text from WordPress feed

functions.php

<?php

/**
 * Remove text from rss feed content and excerpt.
 *
 * @param string $content
 * @return string
 */
function remove_feed_text( $content ) {

	// Replace 'Missing Attachment' text.
	$content = str_replace( 'Missing Attachment', '', $content );

	return $content;
}
add_filter( 'the_excerpt_rss', 'remove_feed_text', 10, 1 );
add_filter( 'the_content_feed', 'remove_feed_text', 10, 1 );