Thread:Extension talk:RSS/flickr tag not parsed inside MediaWiki:Rss-item/reply (7)

Ioannis, see https://git.wikimedia.org/blob/mediawiki%2Fextensions%2FRSS/feaf0e186bc30438af0b025ef938b8a966d3269f/RSSParser.php#L432. In your code, you could try to add the tag you want to allow to the array $extraInclude.