wp-includes/SimplePie/src/Item.php:2342Get the <atom:source> for the item
SimplePie\Source|null public function get_source() { if ($return = $this->get_item_tags(\SimplePie\SimplePie::NAMESPACE_ATOM_10, 'source')) { return $this->registry->create(Source::class, [$this, $return[0]]); } return null; }Introduced in 1.1. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/SimplePie/src/Item.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.