wp-includes/SimplePie/src/Enclosure.php:447Get the expression
string public function get_expression() { if ($this->expression !== null) { return $this->expression; } return 'full'; }Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/SimplePie/src/Enclosure.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.