wp-includes/class-wp-rewrite.php:1715Adds a rewrite rule that doesn't correspond to index.php.
$regexstring$querystring public function add_external_rule( $regex, $query ) { $this->non_wp_rules[ $regex ] = $query; }Introduced in 2.1.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/class-wp-rewrite.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.