wp-includes/class-wp-scripts.php:1032Checks if the provided fetchpriority is valid.
$prioritystring|mixedbool private function is_valid_fetchpriority( $priority ): bool { return in_array( $priority, array( 'auto', 'low', 'high' ), true ); }Introduced in 6.9.0. Unchanged from 6.9.7 through 7.1.0.
Signature, return type and hooks compared across 3 parsed releases.
src/wp-includes/class-wp-scripts.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.