diff --git a/core/includes/image.inc b/core/includes/image.inc
index f6ae7f1..6191179 100644
--- a/core/includes/image.inc
+++ b/core/includes/image.inc
@@ -34,7 +34,7 @@
  */
 
 /**
- * Return a list of available toolkits.
+ * Returns a list of available toolkits.
  *
  * @return
  *   An array with the toolkit names as keys and the descriptions as values.
@@ -55,7 +55,7 @@ function image_get_available_toolkits() {
 }
 
 /**
- * Retrieve the name of the currently used toolkit.
+ * Retrieves the name of the currently used toolkit.
  *
  * @return
  *   String containing the name of the selected toolkit, or FALSE on error.
@@ -101,7 +101,7 @@ function image_toolkit_invoke($method, stdClass $image, array $params = array())
 }
 
 /**
- * Get details about an image.
+ * Gets details about an image.
  *
  * Drupal supports GIF, JPG and PNG file formats when used with the GD
  * toolkit, and may support others, depending on which toolkits are
@@ -261,7 +261,7 @@ function image_scale(stdClass $image, $width = NULL, $height = NULL, $upscale =
 }
 
 /**
- * Resize an image to the given dimensions (ignoring aspect ratio).
+ * Resizes an image to the given dimensions (ignoring aspect ratio).
  *
  * @param $image
  *   An image object returned by image_load().
@@ -284,7 +284,7 @@ function image_resize(stdClass $image, $width, $height) {
 }
 
 /**
- * Rotate an image by the given number of degrees.
+ * Rotates an image by the given number of degrees.
  *
  * @param $image
  *   An image object returned by image_load().
@@ -308,7 +308,7 @@ function image_rotate(stdClass $image, $degrees, $background = NULL) {
 }
 
 /**
- * Crop an image to the rectangle specified by the given rectangle.
+ * Crops an image to the rectangle specified by the given rectangle.
  *
  * @param $image
  *   An image object returned by image_load().
@@ -340,7 +340,7 @@ function image_crop(stdClass $image, $x, $y, $width, $height) {
 }
 
 /**
- * Convert an image to grayscale.
+ * Converts an image to grayscale.
  *
  * @param $image
  *   An image object returned by image_load().
@@ -357,7 +357,7 @@ function image_desaturate(stdClass $image) {
 
 
 /**
- * Load an image file and return an image object.
+ * Loads an image file and returns an image object.
  *
  * Any changes to the file are not saved until image_save() is called.
  *
@@ -400,7 +400,7 @@ function image_load($file, $toolkit = FALSE) {
 }
 
 /**
- * Close the image and save the changes to a file.
+ * Closes the image and saves the changes to a file.
  *
  * @param $image
  *   An image object returned by image_load(). The object's 'info' property
diff --git a/core/includes/install.core.inc b/core/includes/install.core.inc
index 37b3281..d22075d 100644
--- a/core/includes/install.core.inc
+++ b/core/includes/install.core.inc
@@ -9,8 +9,7 @@ use Drupal\Core\Database\Install\TaskException;
  */
 
 /**
- * Global flag to indicate that a task should not be run during the current
- * installation request.
+ * Do not run the task during the current installation request.
  *
  * This can be used to skip running an installation task when certain
  * conditions are met, even though the task may still show on the list of
@@ -23,17 +22,14 @@ use Drupal\Core\Database\Install\TaskException;
 const INSTALL_TASK_SKIP = 1;
 
 /**
- * Global flag to indicate that a task should be run on each installation
- * request that reaches it.
+ * Run the task on each installation request that reaches it.
  *
  * This is primarily used by the Drupal installer for bootstrap-related tasks.
  */
 const INSTALL_TASK_RUN_IF_REACHED = 2;
 
 /**
- * Global flag to indicate that a task should be run on each installation
- * request that reaches it, until the database is set up and we are able to
- * record the fact that it already ran.
+ * Run the task on each installation request until the database is set up.
  *
  * This is the default method for running tasks and should be used for most
  * tasks that occur after the database is set up; these tasks will then run
@@ -203,7 +199,7 @@ function install_state_defaults() {
 }
 
 /**
- * Begin an installation request, modifying the installation state as needed.
+ * Begins an installation request, modifying the installation state as needed.
  *
  * This function performs commands that must run at the beginning of every page
  * request. It throws an exception if the installation should not proceed.
@@ -747,7 +743,7 @@ function install_display_output($output, $install_state) {
 }
 
 /**
- * Installation task; verify the requirements for installing Drupal.
+ * Verifies the requirements for installing Drupal.
  *
  * @param $install_state
  *   An array of information about the current installation state.
@@ -798,7 +794,7 @@ function install_verify_requirements(&$install_state) {
 }
 
 /**
- * Installation task; install the Drupal system module.
+ * Installs the Drupal system module.
  *
  * @param $install_state
  *   An array of information about the current installation state.
@@ -824,7 +820,7 @@ function install_system_module(&$install_state) {
 }
 
 /**
- * Verify and return the last installation task that was completed.
+ * Verifies and returns the last installation task that was completed.
  *
  * @return
  *   The last completed task, if there is one. An exception is thrown if Drupal
@@ -868,7 +864,7 @@ function install_verify_settings() {
 }
 
 /**
- * Verify PDO library.
+ * Verifies the PDO library.
  */
 function install_verify_pdo() {
   // PDO was moved to PHP core in 5.2.0, but the old extension (targeting 5.0
@@ -880,15 +876,13 @@ function install_verify_pdo() {
 }
 
 /**
- * Installation task; define a form to configure and rewrite settings.php.
+ * Form constructor for a form to configure and rewrite settings.php.
  *
- * @param $form_state
- *   An associative array containing the current state of the form.
  * @param $install_state
  *   An array of information about the current installation state.
  *
- * @return
- *   The form API definition for the database configuration form.
+ * @see install_settings_form_validate()
+ * @see install_settings_form_submit()
  */
 function install_settings_form($form, &$form_state, &$install_state) {
   global $databases;
@@ -950,7 +944,9 @@ function install_settings_form($form, &$form_state, &$install_state) {
 }
 
 /**
- * Form API validate for install_settings form.
+ * Form validation handler for install_settings_form().
+ *
+ * @see install_settings_form_submit()
  */
 function install_settings_form_validate($form, &$form_state) {
   $driver = $form_state['values']['driver'];
@@ -1007,7 +1003,9 @@ function install_database_errors($database, $settings_file) {
 }
 
 /**
- * Form API submit for install_settings form.
+ * Form submission handler for install_settings_form().
+ *
+ * @see install_settings_form_validate()
  */
 function install_settings_form_submit($form, &$form_state) {
   global $install_state;
@@ -1067,7 +1065,7 @@ function install_find_profiles() {
 }
 
 /**
- * Installation task; select which profile to install.
+ * Selects which profile to install.
  *
  * @param $install_state
  *   An array of information about the current installation state. The chosen
@@ -1106,8 +1104,7 @@ function install_select_profile(&$install_state) {
 }
 
 /**
- * Helper function for automatically selecting an installation profile from a
- * list or from a selection passed in via $_POST.
+ * Selects an installation profile from a list or from a $_POST submission.
  */
 function _install_select_profile($profiles) {
   if (sizeof($profiles) == 0) {
@@ -1130,10 +1127,8 @@ function _install_select_profile($profiles) {
 }
 
 /**
- * Form API array definition for the profile selection form.
+ * Form constructor for the profile selection form.
  *
- * @param $form_state
- *   Array of metadata about state of form processing.
  * @param $profile_files
  *   Array of .profile files, as returned from file_scan_directory().
  */
@@ -1198,7 +1193,7 @@ function install_select_profile_form($form, &$form_state, $profile_files) {
 }
 
 /**
- * Find all .po files useful for the installer.
+ * Finds all .po files that are useful to the installer.
  */
 function install_find_translations() {
   $files = install_find_translation_files();
@@ -1217,7 +1212,7 @@ function install_find_translations() {
 }
 
 /**
- * Find installer translations either for a specific langcode or all languages.
+ * Finds installer translations either for a specific langcode or all languages.
  *
  * @param $langcode
  *   (optional) The language code corresponding to the language for which we
@@ -1237,7 +1232,7 @@ function install_find_translation_files($langcode = NULL) {
 }
 
 /**
- * Installation task; select which language to use.
+ * Selects which language to use during installation.
  *
  * @param $install_state
  *   An array of information about the current installation state. The chosen
@@ -1320,7 +1315,7 @@ function install_select_language(&$install_state) {
 }
 
 /**
- * Form API array definition for language selection.
+ * Form constructor for the language selection form.
  */
 function install_select_language_form($form, &$form_state, $files) {
   include_once DRUPAL_ROOT . '/core/includes/standard.inc';
@@ -1386,7 +1381,7 @@ function install_already_done_error() {
 }
 
 /**
- * Installation task; load information about the chosen profile.
+ * Loads information about the chosen profile during installation.
  *
  * @param $install_state
  *   An array of information about the current installation state. The loaded
@@ -1405,7 +1400,7 @@ function install_load_profile(&$install_state) {
 }
 
 /**
- * Installation task; perform a full bootstrap of Drupal.
+ * Performs a full bootstrap of Drupal during installation.
  *
  * @param $install_state
  *   An array of information about the current installation state.
@@ -1415,7 +1410,7 @@ function install_bootstrap_full(&$install_state) {
 }
 
 /**
- * Installation task; install required modules via a batch process.
+ * Installs required modules via a batch process.
  *
  * @param $install_state
  *   An array of information about the current installation state.
@@ -1468,7 +1463,7 @@ function install_profile_modules(&$install_state) {
 }
 
 /**
- * Installation task; import languages via a batch process.
+ * Imports languages via a batch process during installation.
  *
  * @param $install_state
  *   An array of information about the current installation state.
@@ -1509,15 +1504,13 @@ function install_import_translations(&$install_state) {
 }
 
 /**
- * Installation task; configure settings for the new site.
+ * Form constructor for a form to configure the new site.
  *
- * @param $form_state
- *   An associative array containing the current state of the form.
  * @param $install_state
  *   An array of information about the current installation state.
  *
- * @return
- *   The form API definition for the site configuration form.
+ * @see install_configure_form_validate()
+ * @see install_configure_form_submit()
  */
 function install_configure_form($form, &$form_state, &$install_state) {
   drupal_set_title(st('Configure site'));
@@ -1563,7 +1556,7 @@ function install_configure_form($form, &$form_state, &$install_state) {
 }
 
 /**
- * Installation task; finish importing files at end of installation.
+ * Finishes importing files at end of installation.
  *
  * @param $install_state
  *   An array of information about the current installation state.
@@ -1582,7 +1575,7 @@ function install_import_translations_remaining(&$install_state) {
 }
 
 /**
- * Installation task; perform final steps and display a 'finished' page.
+ * Performs final installation steps and displays a 'finished' page.
  *
  * @param $install_state
  *   An array of information about the current installation state.
@@ -1769,7 +1762,11 @@ function install_check_requirements($install_state) {
 }
 
 /**
- * Forms API array definition for site configuration.
+ * Returns a Forms API array definition for site configuration.
+ *
+ * @see install_configure_form()
+ * @see install_configure_form_validate()
+ * @see install_configure_form_submit()
  */
 function _install_configure_form($form, &$form_state, &$install_state) {
   $form['site_information'] = array(
@@ -1880,7 +1877,9 @@ function _install_configure_form($form, &$form_state, &$install_state) {
 }
 
 /**
- * Forms API validate for the site configuration form.
+ * Form validation handler for install_configure_form().
+ *
+ * @see install_configure_form_submit()
  */
 function install_configure_form_validate($form, &$form_state) {
   if ($error = user_validate_name($form_state['values']['account']['name'])) {
@@ -1889,7 +1888,9 @@ function install_configure_form_validate($form, &$form_state) {
 }
 
 /**
- * Forms API submit for the site configuration form.
+ * Form submission handler for install_configure_form().
+ *
+ * @see install_configure_form_validate()
  */
 function install_configure_form_submit($form, &$form_state) {
   global $user;
diff --git a/core/includes/install.inc b/core/includes/install.inc
index 72adf1c..4cd092b 100644
--- a/core/includes/install.inc
+++ b/core/includes/install.inc
@@ -4,6 +4,11 @@ use Drupal\Core\Database\Database;
 use Drupal\Core\Config\SignedFileStorage;
 
 /**
+ * @file
+ * API functions for installing modules and themes.
+ */
+
+/**
  * Indicates that a module has not been installed yet.
  */
 const SCHEMA_UNINSTALLED = -1;
@@ -74,7 +79,7 @@ const FILE_NOT_WRITABLE = 64;
 const FILE_NOT_EXECUTABLE = 128;
 
 /**
- * Initialize the update system by loading all installed module's .install files.
+ * Loads .install files for installed modules to initialize the update system.
  */
 function drupal_load_updates() {
   foreach (drupal_get_installed_schema_version(NULL, FALSE, TRUE) as $module => $schema_version) {
@@ -109,11 +114,12 @@ function drupal_install_profile_distribution_name() {
 }
 
 /**
- * Auto detect the base_url with PHP predefined variables.
+ * Detects the base URL using the PHP $_SERVER variables.
  *
  * @param $file
  *   The name of the file calling this function so we can strip it out of
  *   the URI when generating the base_url.
+ *
  * @return
  *   The auto-detected $base_url that should be configured in settings.php
  */
@@ -128,7 +134,7 @@ function drupal_detect_baseurl($file = 'core/install.php') {
 }
 
 /**
- * Detect all supported databases that are compiled into PHP.
+ * Detects all supported databases that are compiled into PHP.
  *
  * @return
  *  An array of database types compiled into PHP.
@@ -144,7 +150,7 @@ function drupal_detect_database_types() {
 }
 
 /**
- * Return all supported database installer objects that are compiled into PHP.
+ * Returns all supported database installer objects that are compiled into PHP.
  *
  * @return
  *  An array of database installer objects compiled into PHP.
@@ -183,7 +189,7 @@ function drupal_get_database_types() {
 }
 
 /**
- * Replace values in settings.php with values in the submitted array.
+ * Replaces values in settings.php with values in the submitted array.
  *
  * @param $settings
  *   An array of settings that need to be updated.
@@ -261,10 +267,11 @@ function drupal_rewrite_settings($settings = array()) {
 }
 
 /**
- * Verify an install profile for installation.
+ * Verifies an install profile for installation.
  *
  * @param $install_state
  *   An array of information about the current installation state.
+ *
  * @return
  *   The list of modules to install.
  */
@@ -312,7 +319,7 @@ function drupal_verify_profile($install_state) {
 }
 
 /**
- * Callback to install the system module.
+ * Installs the system module.
  *
  * Separated from the installation of other modules so core system
  * functions can be made available while other modules are installed.
@@ -423,7 +430,7 @@ function drupal_uninstall_modules($module_list = array(), $uninstall_dependents
 }
 
 /**
- * Verify the state of the specified file.
+ * Verifies the state of the specified file.
  *
  * @param $file
  *   The file to check for.
@@ -431,6 +438,7 @@ function drupal_uninstall_modules($module_list = array(), $uninstall_dependents
  *   An optional bitmask created from various FILE_* constants.
  * @param $type
  *   The type of file. Can be file (default), dir, or link.
+ *
  * @return
  *   TRUE on success or FALSE on failure. A message is set for the latter.
  */
@@ -502,7 +510,7 @@ function drupal_verify_install_file($file, $mask = NULL, $type = 'file') {
 }
 
 /**
- * Create a directory with specified permissions.
+ * Creates a directory with the specified permissions.
  *
  * @param $file
  *  The name of the directory to create;
@@ -510,6 +518,7 @@ function drupal_verify_install_file($file, $mask = NULL, $type = 'file') {
  *  The permissions of the directory to create.
  * @param $message
  *  (optional) Whether to output messages. Defaults to TRUE.
+ *
  * @return
  *  TRUE/FALSE whether or not the directory was successfully created.
  */
@@ -541,7 +550,7 @@ function drupal_install_mkdir($file, $mask, $message = TRUE) {
 }
 
 /**
- * Attempt to fix file permissions.
+ * Attempts to fix file permissions.
  *
  * The general approach here is that, because we do not know the security
  * setup of the webserver, we apply our permission changes to all three
@@ -558,6 +567,7 @@ function drupal_install_mkdir($file, $mask, $message = TRUE) {
  *  The desired permissions for the file.
  * @param $message
  *  (optional) Whether to output messages. Defaults to TRUE.
+ *
  * @return
  *  TRUE/FALSE whether or not we were able to fix the file's permissions.
  */
@@ -623,7 +633,7 @@ function drupal_install_fix_file($file, $mask, $message = TRUE) {
 }
 
 /**
- * Send the user to a different installer page.
+ * Sends the user to a different installer page.
  *
  * This issues an on-site HTTP redirect. Messages (and errors) are erased.
  *
@@ -701,7 +711,7 @@ function drupal_requirements_url($severity) {
 }
 
 /**
- * Functional equivalent of t(), used when some systems are not available.
+ * Translates a string when some systems are not available.
  *
  * Used during the install process, when database, theme, and localization
  * system is possibly not yet available.
@@ -761,10 +771,11 @@ function st($string, array $args = array(), array $options = array()) {
 }
 
 /**
- * Check an install profile's requirements.
+ * Checks an install profile's requirements.
  *
  * @param $profile
  *   Name of install profile to check.
+ *
  * @return
  *   Array of the install profile's requirements.
  */
@@ -792,11 +803,12 @@ function drupal_check_profile($profile) {
 }
 
 /**
- * Extract highest severity from requirements array.
+ * Extracts the highest severity from the requirements array.
  *
  * @param $requirements
  *   An array of requirements, in the same format as is returned by
  *   hook_requirements().
+ *
  * @return
  *   The highest severity in the array.
  */
@@ -811,10 +823,11 @@ function drupal_requirements_severity(&$requirements) {
 }
 
 /**
- * Check a module's requirements.
+ * Checks a module's requirements.
  *
  * @param $module
  *   Machine name of module to check.
+ *
  * @return
  *   TRUE/FALSE depending on the requirements are in place.
  */
@@ -841,13 +854,14 @@ function drupal_check_module($module) {
 }
 
 /**
- * Retrieve info about an install profile from its .info file.
+ * Retrieves information about an install profile from its .info file.
  *
  * The information stored in a profile .info file is similar to that stored in
  * a normal Drupal module .info file. For example:
  * - name: The real name of the install profile for display purposes.
  * - description: A brief description of the profile.
- * - dependencies: An array of shortnames of other modules this install profile requires.
+ * - dependencies: An array of shortnames of other modules that this install
+ *   profile requires.
  *
  * Additional, less commonly-used information that can appear in a profile.info
  * file but not in a normal Drupal module .info file includes:
diff --git a/core/includes/language.inc b/core/includes/language.inc
index 2c46c76..82edaba 100644
--- a/core/includes/language.inc
+++ b/core/includes/language.inc
@@ -376,7 +376,7 @@ function language_from_default() {
 }
 
 /**
- * Split the given path into prefix and actual path.
+ * Splits the given path into prefix and actual path.
  *
  * Parse the given path and return the language object identified by the
  * prefix and the actual path.
@@ -409,10 +409,10 @@ function language_url_split_prefix($path, $languages) {
 }
 
 /**
- * Return the possible fallback languages ordered by language weight.
+ * Returns the possible fallback languages ordered by language weight.
  *
  * @param
- *   The language type.
+ *   (optional) The language type. Defaults to LANGUAGE_TYPE_CONTENT.
  *
  * @return
  *   An array of language codes.
diff --git a/core/includes/mail.inc b/core/includes/mail.inc
index f58a76e..c1da474 100644
--- a/core/includes/mail.inc
+++ b/core/includes/mail.inc
@@ -13,7 +13,7 @@
 define('MAIL_LINE_ENDINGS', isset($_SERVER['WINDIR']) || strpos($_SERVER['SERVER_SOFTWARE'], 'Win32') !== FALSE ? "\r\n" : "\n");
 
 /**
- * Compose and optionally send an e-mail message.
+ * Composes and optionally sends an e-mail message.
  *
  * Sending an e-mail works with defining an e-mail template (subject, text
  * and possibly e-mail headers) and the replacement values to use in the
@@ -191,8 +191,7 @@ function drupal_mail($module, $key, $to, $language, $params = array(), $from = N
 }
 
 /**
- * Returns an object that implements the Drupal\Core\Mail\MailInterface
- * interface.
+ * Returns an object that implements Drupal\Core\Mail\MailInterface.
  *
  * Allows for one or more custom mail backends to format and send mail messages
  * composed using drupal_mail().
@@ -287,7 +286,7 @@ function drupal_mail_system($module, $key) {
 }
 
 /**
- * Perform format=flowed soft wrapping for mail (RFC 3676).
+ * Performs format=flowed soft wrapping for mail (RFC 3676).
  *
  * We use delsp=yes wrapping, but only break non-spaced languages when
  * absolutely necessary to avoid compatibility issues.
@@ -330,8 +329,7 @@ function drupal_wrap_mail($text, $indent = '') {
 }
 
 /**
- * Transform an HTML string into plain text, preserving the structure of the
- * markup. Useful for preparing the body of a node to be sent by e-mail.
+ * Transforms an HTML string into plain text, preserving its structure.
  *
  * The output will be suitable for use as 'format=flowed; delsp=yes' text
  * (RFC 3676) and can be passed directly to drupal_mail() for sending.
@@ -510,9 +508,9 @@ function drupal_html_to_text($string, $allowed_tags = NULL) {
 }
 
 /**
- * Helper function for array_walk in drupal_wrap_mail().
- *
  * Wraps words on a single line.
+ *
+ * Callback for array_walk() winthin drupal_wrap_mail().
  */
 function _drupal_wrap_mail_line(&$line, $key, $values) {
   // Use soft-breaks only for purely quoted or unindented text.
@@ -522,9 +520,9 @@ function _drupal_wrap_mail_line(&$line, $key, $values) {
 }
 
 /**
- * Helper function for drupal_html_to_text().
- *
  * Keeps track of URLs and replaces them with placeholder tokens.
+ *
+ * Callback for preg_replace_callback() within drupal_html_to_text().
  */
 function _drupal_html_to_mail_urls($match = NULL, $reset = FALSE) {
   global $base_url, $base_path;
@@ -549,18 +547,18 @@ function _drupal_html_to_mail_urls($match = NULL, $reset = FALSE) {
 }
 
 /**
- * Helper function for drupal_wrap_mail() and drupal_html_to_text().
+ * Replaces non-quotation markers from a given piece of indentation with spaces.
  *
- * Replace all non-quotation markers from a given piece of indentation with spaces.
+ * Callback for array_map() within drupal_html_to_text().
  */
 function _drupal_html_to_text_clean($indent) {
   return preg_replace('/[^>]/', ' ', $indent);
 }
 
 /**
- * Helper function for drupal_html_to_text().
+ * Pads the last line with the given character.
  *
- * Pad the last line with the given character.
+ * @see drupal_html_to_text()
  */
 function _drupal_html_to_text_pad($text, $pad, $prefix = '') {
   // Remove last line break.
diff --git a/core/includes/menu.inc b/core/includes/menu.inc
index fecd158..520e6e6 100644
--- a/core/includes/menu.inc
+++ b/core/includes/menu.inc
@@ -2094,8 +2094,6 @@ function menu_local_tasks($level = 0) {
  * local tasks for a given system path. All local tasks of the tab type
  * MENU_CONTEXT_INLINE are taken into account.
  *
- * @see hook_menu()
- *
  * For example, when considering the following registered local tasks:
  * - node/%node/view (default local task) with no 'context' defined
  * - node/%node/edit with context: MENU_CONTEXT_PAGE | MENU_CONTEXT_INLINE
@@ -2123,6 +2121,7 @@ function menu_local_tasks($level = 0) {
  *   A list of menu router items that are local tasks for the passed-in path.
  *
  * @see contextual_links_preprocess()
+ * @see hook_menu()
  */
 function menu_contextual_links($module, $parent_path, $args) {
   static $path_empty = array();
@@ -3177,6 +3176,7 @@ function menu_link_save(&$item, $existing_item = array(), $parent_candidates = a
  *   A menu link.
  * @param $parent_candidates
  *   An array of menu links keyed by mlid.
+ *
  * @return
  *   A menu link structure of the possible parent or FALSE if no valid parent
  *   has been found.