wp-includes/rss.php:223$p$text function feed_cdata ($p, $text) { if ($this->feed_type == ATOM and $this->incontent) { $this->append_content( $text ); } else { $current_el = join('_', array_reverse($this->stack)); $this->append($current_el, $text); } }Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/rss.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.