diff --git a/lib/ajax/ajaxlib.php b/lib/ajax/ajaxlib.php
index f7d378f287ea0..3880c78e41ed2 100644
--- a/lib/ajax/ajaxlib.php
+++ b/lib/ajax/ajaxlib.php
@@ -1,5 +1,4 @@
 <?php
-
 // This file is part of Moodle - http://moodle.org/
 //
 // Moodle is free software: you can redistribute it and/or modify
@@ -25,16 +24,14 @@
  */
 
 /**
- * You need to call this function if you wish to use the set_user_preference
- * method in javascript_static.php, to white-list the preference you want to update
- * from JavaScript, and to specify the type of cleaning you expect to be done on
- * values.
+ * You need to call this function if you wish to use the set_user_preference method in javascript_static.php, to white-list the
+ * preference you want to update from JavaScript, and to specify the type of cleaning you expect to be done on values.
  *
- * @param string $name the name of the user_perference we should allow to be
- *      updated by remote calls.
- * @param integer $paramtype one of the PARAM_{TYPE} constants, user to clean
- *      submitted values before set_user_preference is called.
- * @return void
+ * @package  core_preference
+ * @category preference
+ * @param    string          $name      the name of the user_perference we should allow to be updated by remote calls.
+ * @param    integer         $paramtype one of the PARAM_{TYPE} constants, user to clean submitted values before set_user_preference is called.
+ * @return   null
  */
 function user_preference_allow_ajax_update($name, $paramtype) {
     global $USER, $PAGE;
diff --git a/lib/ajax/setuserpref.php b/lib/ajax/setuserpref.php
index ca94ccbd20072..884a5ecad27dc 100644
--- a/lib/ajax/setuserpref.php
+++ b/lib/ajax/setuserpref.php
@@ -1,35 +1,30 @@
 <?php
-
-///////////////////////////////////////////////////////////////////////////
-//                                                                       //
-// NOTICE OF COPYRIGHT                                                   //
-//                                                                       //
-// Moodle - Modular Object-Oriented Dynamic Learning Environment         //
-//          http://moodle.org                                            //
-//                                                                       //
-// Copyright (C) 1999 onwards Martin Dougiamas  http://dougiamas.com     //
-//                                                                       //
-// This program is free software; you can redistribute it and/or modify  //
-// it under the terms of the GNU General Public License as published by  //
-// the Free Software Foundation; either version 2 of the License, or     //
-// (at your option) any later version.                                   //
-//                                                                       //
-// This program is distributed in the hope that it will be useful,       //
-// but WITHOUT ANY WARRANTY; without even the implied warranty of        //
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         //
-// GNU General Public License for more details:                          //
-//                                                                       //
-//          http://www.gnu.org/copyleft/gpl.html                         //
-//                                                                       //
-///////////////////////////////////////////////////////////////////////////
-
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+ 
+ 
 /**
- * Code to update a user preference in response to an ajax call. You should not
- * send requests to this script directly. Instead use the set_user_preference
+ * Code to update a user preference in response to an ajax call.
+ *
+ * You should not send requests to this script directly. Instead use the set_user_preference
  * function in javascript_static.js.
  *
- * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
- * @package moodlecore
+ * @package    core_preference
+ * @category   preference
+ * @copyright  Copyright (C) 1999 onwards Martin Dougiamas  http://dougiamas.com
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU Public License
  */
 
 require_once(dirname(__FILE__) . '/../../config.php');
diff --git a/lib/moodlelib.php b/lib/moodlelib.php
index 9d249dd498fac..2a55f7300f8e8 100644
--- a/lib/moodlelib.php
+++ b/lib/moodlelib.php
@@ -1,5 +1,4 @@
 <?php
-
 // This file is part of Moodle - http://moodle.org/
 //
 // Moodle is free software: you can redistribute it and/or modify
@@ -1558,7 +1557,7 @@ function gc_cache_flags() {
     return true;
 }
 
-/// FUNCTIONS FOR HANDLING USER PREFERENCES ////////////////////////////////////
+// USER PREFERENCE API
 
 /**
  * Refresh user preference cache. This is used most often for $USER
@@ -1566,9 +1565,13 @@ function gc_cache_flags() {
  *
  * Preferences for each user are loaded on first use on every page, then again after the timeout expires.
  *
- * @param stdClass $user user object, preferences are preloaded into ->preference property
- * @param int $cachelifetime cache life time on the current page (ins seconds)
- * @return void
+ * @package  core
+ * @category preference
+ * @access   public
+ * @param    stdClass         $user          User object. Preferences are preloaded into 'preference' property
+ * @param    int              $cachelifetime Cache life time on the current page (in seconds)
+ * @throws   coding_exception
+ * @return   null
  */
 function check_user_preferences_loaded(stdClass $user, $cachelifetime = 120) {
     global $DB;
@@ -1608,13 +1611,14 @@ function check_user_preferences_loaded(stdClass $user, $cachelifetime = 120) {
 }
 
 /**
- * Called from set/delete_user_preferences, so that the prefs can
+ * Called from set/unset_user_preferences, so that the prefs can
  * be correctly reloaded in different sessions.
  *
  * NOTE: internal function, do not call from other code.
  *
- * @param integer $userid the user whose prefs were changed.
- * @return void
+ * @package core
+ * @access  private
+ * @param   integer         $userid the user whose prefs were changed.
  */
 function mark_user_preferences_changed($userid) {
     global $CFG;
@@ -1630,13 +1634,17 @@ function mark_user_preferences_changed($userid) {
 /**
  * Sets a preference for the specified user.
  *
- * If user object submitted, 'preference' property contains the preferences cache.
+ * If a $user object is submitted it's 'preference' property is used for the preferences cache.
  *
- * @param string $name The key to set as preference for the specified user
- * @param string $value The value to set for the $name key in the specified user's record,
- *                      null means delete current value
- * @param stdClass|int $user A moodle user object or id, null means current user
- * @return bool always true or exception
+ * @package  core
+ * @category preference
+ * @access   public
+ * @param    string            $name  The key to set as preference for the specified user
+ * @param    string            $value The value to set for the $name key in the specified user's
+ *                                    record, null means delete current value.
+ * @param    stdClass|int|null $user  A moodle user object or id, null means current user
+ * @throws   coding_exception
+ * @return   bool                     Always true or exception
  */
 function set_user_preference($name, $value, $user = null) {
     global $USER, $DB;
@@ -1703,11 +1711,14 @@ function set_user_preference($name, $value, $user = null) {
 /**
  * Sets a whole array of preferences for the current user
  *
- * If user object submitted, 'preference' property contains the preferences cache.
+ * If a $user object is submitted it's 'preference' property is used for the preferences cache.
  *
- * @param array $prefarray An array of key/value pairs to be set
- * @param stdClass|int $user A moodle user object or id, null means current user
- * @return bool always true or exception
+ * @package  core
+ * @category preference
+ * @access   public
+ * @param    array             $prefarray An array of key/value pairs to be set
+ * @param    stdClass|int|null $user      A moodle user object or id, null means current user
+ * @return   bool                         Always true or exception
  */
 function set_user_preferences(array $prefarray, $user = null) {
     foreach ($prefarray as $name => $value) {
@@ -1719,11 +1730,15 @@ function set_user_preferences(array $prefarray, $user = null) {
 /**
  * Unsets a preference completely by deleting it from the database
  *
- * If user object submitted, 'preference' property contains the preferences cache.
+ * If a $user object is submitted it's 'preference' property is used for the preferences cache.
  *
- * @param string  $name The key to unset as preference for the specified user
- * @param stdClass|int $user A moodle user object or id, null means current user
- * @return bool always true or exception
+ * @package  core
+ * @category preference
+ * @access   public
+ * @param    string            $name The key to unset as preference for the specified user
+ * @param    stdClass|int|null $user A moodle user object or id, null means current user
+ * @throws   coding_exception
+ * @return   bool                    Always true or exception
  */
 function unset_user_preference($name, $user = null) {
     global $USER, $DB;
@@ -1773,12 +1788,17 @@ function unset_user_preference($name, $user = null) {
  * none is found, then the optional value $default is returned,
  * otherwise NULL.
  *
- * If user object submitted, 'preference' property contains the preferences cache.
- *
- * @param string $name Name of the key to use in finding a preference value
- * @param mixed $default Value to be returned if the $name key is not set in the user preferences
- * @param stdClass|int $user A moodle user object or id, null means current user
- * @return mixed string value or default
+ * If a $user object is submitted it's 'preference' property is used for the preferences cache.
+ *
+ * @package  core
+ * @category preference
+ * @access   public
+ * @param    string            $name    Name of the key to use in finding a preference value
+ * @param    mixed|null        $default Value to be returned if the $name key is not set in the user preferences
+ * @param    stdClass|int|null $user    A moodle user object or id, null means current user
+ * @throws   coding_exception
+ * @return   string|mixed|null          A string containing the value of a single preference. An
+ *                                      array with all of the preferences or null
  */
 function get_user_preferences($name = null, $default = null, $user = null) {
     global $USER;