wp-includes/SimplePie/src/Enclosure.php:309Get all captions
SimplePie\Caption[]|null public function get_captions() { if ($this->captions !== null) { return $this->captions; } return null; }One change between 6.7.7 and 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
array|null to SimplePie\Caption[]|null.verified against sourcesrc/wp-includes/SimplePie/src/Enclosure.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.