diff --git a/wp-admin/options-discussion.php b/wp-admin/options-discussion.php
index 3f302be326..76f6b3226e 100644
--- a/wp-admin/options-discussion.php
+++ b/wp-admin/options-discussion.php
@@ -5,7 +5,6 @@
  * @package WordPress
  * @subpackage Administration
  */
-
 /** WordPress Administration Bootstrap */
 require_once( dirname( __FILE__ ) . '/admin.php' );
 
@@ -77,7 +76,13 @@ include( ABSPATH . 'wp-admin/admin-header.php' );
 <label for="thread_comments">
 <input name="thread_comments" type="checkbox" id="thread_comments" value="1" <?php checked('1', get_option('thread_comments')); ?> />
 <?php
-
+/**
+ * Filter the maximum depth of threaded/nested comments.
+ *
+ * @since 2.7.0.
+ *
+ * @param int $10 The maximum depth of threaded comments. Default 10.
+ */
 $maxdeep = (int) apply_filters( 'thread_comments_depth_max', 10 );
 
 $thread_comments_depth = '</label><label for="thread_comments_depth"><select name="thread_comments_depth" id="thread_comments_depth">';
@@ -219,7 +224,17 @@ $avatar_defaults = array(
 	'monsterid' => __('MonsterID (Generated)'),
 	'retro' => __('Retro (Generated)')
 );
-$avatar_defaults = apply_filters('avatar_defaults', $avatar_defaults);
+/**
+ * Filter the default avatars.
+ *
+ * Avatars are stored in key/value pairs, where the key is option value,
+ * and the name is the displayed avatar name.
+ *
+ * @since 2.6.0
+ *
+ * @param array $avatar_defaults Array of default avatars.
+ */
+$avatar_defaults = apply_filters( 'avatar_defaults', $avatar_defaults );
 $default = get_option('avatar_default');
 if ( empty($default) )
 	$default = 'mystery';
@@ -235,7 +250,14 @@ foreach ( $avatar_defaults as $default_key => $default_name ) {
 	$avatar_list .= ' ' . $default_name . '</label>';
 	$avatar_list .= '<br />';
 }
-echo apply_filters('default_avatar_select', $avatar_list);
+/**
+ * Filter the HTML output of the default avatar list.
+ *
+ * @since 2.6.0
+ *
+ * @param string $avatar_list HTML markup of the avatar list.
+ */
+echo apply_filters( 'default_avatar_select', $avatar_list );
 ?>
 
 </fieldset></td>