wp-includes/rss.php:387$k$v function map_attrs($k, $v) { return "$k=\"$v\""; }Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/rss.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.