wp-includes/SimplePie/src/Item.php:767Get the posting date/time for the item (UTC time)
$date_formatstringoptional'j F Y, g:i a'int|string|null public function get_gmdate($date_format = 'j F Y, g:i a') { $date = $this->get_date('U'); if ($date === null) { return null; } return gmdate($date_format, $date); }One change between 6.7.7 and 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
int|string|null to string|null.verified against sourcesrc/wp-includes/SimplePie/src/Item.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.