diff --git a/src/wp-includes/widgets/class-wp-widget-categories.php b/src/wp-includes/widgets/class-wp-widget-categories.php
index fcb74a6818..876aa0688f 100644
--- a/src/wp-includes/widgets/class-wp-widget-categories.php
+++ b/src/wp-includes/widgets/class-wp-widget-categories.php
@@ -17,16 +17,26 @@
  */
 class WP_Widget_Categories extends WP_Widget {
 
+	/**
+	 * Sets up a new Categories widget instance.
+	 *
+	 * @since 2.8.0
+	 * @access public
+	 */
 	public function __construct() {
 		$widget_ops = array( 'classname' => 'widget_categories', 'description' => __( "A list or dropdown of categories." ) );
 		parent::__construct('categories', __('Categories'), $widget_ops);
 	}
 
 	/**
-	 * @staticvar bool $first_dropdown
+	 * Outputs the content for the current Categories widget instance.
 	 *
-	 * @param array $args
-	 * @param array $instance
+	 * @since 2.8.0
+	 * @access public
+	 *
+	 * @param array $args     Display arguments including 'before_title', 'after_title',
+	 *                        'before_widget', and 'after_widget'.
+	 * @param array $instance Settings for the current Categories widget instance.
 	 */
 	public function widget( $args, $instance ) {
 		static $first_dropdown = true;
@@ -73,7 +83,7 @@ class WP_Widget_Categories extends WP_Widget {
 			 * @param array $cat_args An array of Categories widget drop-down arguments.
 			 */
 			wp_dropdown_categories( apply_filters( 'widget_categories_dropdown_args', $cat_args ) );
-?>
+			?>
 
 <script type='text/javascript'>
 /* <![CDATA[ */
@@ -113,9 +123,15 @@ class WP_Widget_Categories extends WP_Widget {
 	}
 
 	/**
-	 * @param array $new_instance
-	 * @param array $old_instance
-	 * @return array
+	 * Handles updating settings for the current Categories widget instance.
+	 *
+	 * @since 2.8.0
+	 * @access public
+	 *
+	 * @param array $new_instance New settings for this instance as input by the user via
+	 *                            WP_Widget::form().
+	 * @param array $old_instance Old settings for this instance.
+	 * @return array Updated settings to save.
 	 */
 	public function update( $new_instance, $old_instance ) {
 		$instance = $old_instance;
@@ -129,7 +145,12 @@ class WP_Widget_Categories extends WP_Widget {
 	}
 
 	/**
-	 * @param array $instance
+	 * Outputs the settings form for the Categories widget.
+	 *
+	 * @since 2.8.0
+	 * @access public
+	 *
+	 * @param array $instance Current settings.
 	 */
 	public function form( $instance ) {
 		//Defaults
@@ -139,7 +160,7 @@ class WP_Widget_Categories extends WP_Widget {
 		$hierarchical = isset( $instance['hierarchical'] ) ? (bool) $instance['hierarchical'] : false;
 		$dropdown = isset( $instance['dropdown'] ) ? (bool) $instance['dropdown'] : false;
 		$current_taxonomy = $this->_get_current_taxonomy( $instance );
-?>
+		?>
 		<p><label for="<?php echo $this->get_field_id('title'); ?>"><?php _e( 'Title:' ); ?></label>
 		<input class="widefat" id="<?php echo $this->get_field_id('title'); ?>" name="<?php echo $this->get_field_name('title'); ?>" type="text" value="<?php echo esc_attr( $title ); ?>" /></p>
 
@@ -165,11 +186,11 @@ class WP_Widget_Categories extends WP_Widget {
 
 		<input type="checkbox" class="checkbox" id="<?php echo $this->get_field_id('hierarchical'); ?>" name="<?php echo $this->get_field_name('hierarchical'); ?>"<?php checked( $hierarchical ); ?> />
 		<label for="<?php echo $this->get_field_id('hierarchical'); ?>"><?php _e( 'Show hierarchy' ); ?></label></p>
-<?php
+		<?php
 	}
 
 	/**
-	 * Retrieves the taxonomy for the current widget instance.
+	 * Retrieves the taxonomy for the current Categories widget instance.
 	 *
 	 * @since 4.4.0
 	 * @access public