wp-includes/SimplePie/src/SimplePie.php:2281Get the base URL value from the feed
$elementarrayoptional[]string public function get_base($element = []) { if (!empty($element['xml_base_explicit']) && isset($element['xml_base'])) { return $element['xml_base']; } elseif ($this->get_link() !== null) { return $this->get_link(); } return $this->subscribe_url(); }Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/SimplePie/src/SimplePie.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.