wp-includes/category-template.php:1137Retrieves HTML dropdown (select) content for category list.
$argsmixedstringfunction walk_category_dropdown_tree( ...$args ) { // The user's options are the third parameter. if ( empty( $args[2]['walker'] ) || ! ( $args[2]['walker'] instanceof Walker ) ) { $walker = new Walker_CategoryDropdown(); } else { /** * @var Walker $walker */ $walker = $args[2]['walker']; } return $walker->walk( ...$args );}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/category-template.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.