wp-includes/SimplePie/src/Misc.php:2163Get the default user agent string
string public static function get_default_useragent() { return \SimplePie\SimplePie::NAME . '/' . \SimplePie\SimplePie::VERSION . ' (Feed Parser; ' . \SimplePie\SimplePie::URL . '; Allow like Gecko) Build/' . static::get_build(); }Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/SimplePie/src/Misc.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.