wp-includes/SimplePie/src/Parse/Date.php:640Parse a date
$datestringint public function parse($date) { foreach ($this->user as $method) { if (($returned = call_user_func($method, $date)) !== false) { return $returned; } } foreach ($this->built_in as $method) { if (($returned = call_user_func([$this, $method], $date)) !== false) { return $returned; } } return false; }One change between 6.7.7 and 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
int to int|false.verified against sourcesrc/wp-includes/SimplePie/src/Parse/Date.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.