In which folder can we find the core wordpress Widgets such as Menu Widget

Question

I am a novice in WordPress theme development. I am trying to build a custom Code menu widget for the footer, which is totally different from the default menu widget provided by the WordPress, but I could not understand from where to start. The best will be If I can find the default widget created by the WordPress. I can get some clue and move on.

I have created this with the help of some videos on YouTube →

class chimp_footer_menu extends WP_Widget {
function construct() {
    //Create Widget
    parent::__construct(
        'footer_menu_widget',
        __('The Footer menu Widget','text_domain'),
        array( 'description' => __('A Footer Menu Widget', 'text_domain' )));

}

// Front End display
public function widget($args, $instance) {

}

// Backend Form
public function form($instance) {
    if (isset ($instance['title'])) {
        $title = $instance['title'];
    }
    else {
        $title = __('New Title','text_domain');
    }
}

// Update Widget Values
public function update($new_instance, $old_instance) {}

}

add_action('widgets_init', function(){
    register_widget('chimp_footer_menu');
});

Answer 1

You will find the source of Custom Menu widget in /wp-includes/widgets/class-wp-nav-menu-widget.php.