diff --git a/core/includes/ajax.inc b/core/includes/ajax.inc
index 31fbfc6..5cff7b2 100644
--- a/core/includes/ajax.inc
+++ b/core/includes/ajax.inc
@@ -8,223 +8,155 @@
 use Drupal\Core\Form\FormStateInterface;
 
 /**
- * @defgroup ajax Ajax framework
+ * @defgroup ajax Ajax API
  * @{
- * Functions for Drupal's Ajax framework.
+ * Functions for Drupal's Ajax API.
  *
- * Drupal's Ajax framework is used to dynamically update parts of a page's HTML
- * based on data from the server. Upon a specified event, such as a button
- * click, a callback function is triggered which performs server-side logic and
- * may return updated markup, which is then replaced on-the-fly with no page
- * refresh necessary.
+ * @section sec_overview Overview of Ajax
+ * Ajax is the process of dynamically updating parts of a page's HTML based on
+ * data from the server. When a specified event takes place, a PHP callback is
+ * triggered, which performs server-side logic and may return updated markup or
+ * JavaScript commands to run. After the return, the browser runs the JavaScript
+ * or updates the markup on the fly, with no full page refresh necessary.
  *
- * This framework creates a PHP macro language that allows the server to
- * instruct JavaScript to perform actions on the client browser. When using
- * forms, it can be used with the #ajax property.
- * The #ajax property can be used to bind events to the Ajax framework. By
- * default, #ajax uses 'system/ajax' as its path for submission and thus calls
- * \Drupal\system\FormAjaxController::content() and a defined #ajax['callback']
- * function. However, you may optionally specify a different path to request or
- * a different callback function to invoke, which can return updated HTML or can
- * also return a richer set of
- * @link ajax_commands Ajax framework commands @endlink.
+ * Many different events can trigger Ajax responses, including:
+ * - Clicking a button
+ * - Pressing a key
+ * - Moving the mouse
  *
- * Standard form handling is as follows:
- *   - A form element has a #ajax property that includes #ajax['callback'] and
- *     omits #ajax['path']. See below about using #ajax['path'] to implement
- *     advanced use-cases that require something other than standard form
- *     handling.
- *   - On the specified element, Ajax processing is triggered by a change to
- *     that element.
- *   - The browser submits an HTTP POST request to the 'system/ajax' Drupal
- *     path.
- *   - The controller for the route '/system/ajax',
- *     \Drupal\system\FormAjaxController::content(), calls drupal_process_form()
- *     to process the form submission and rebuild the form if necessary. The
- *     form is processed in much the same way as if it were submitted without
- *     Ajax, with the same #process functions and validation and submission
- *     handlers called in either case, making it easy to create Ajax-enabled
- *     forms that degrade gracefully when JavaScript is disabled.
- *   - After form processing is complete,
- *     \Drupal\system\FormAjaxController::content() calls the function named by
- *     #ajax['callback'], which returns the form element that has been updated
- *     and needs to be returned to the browser, or alternatively, an array of
- *     custom Ajax commands.
- *   - The array is serialized using
- *     \Drupal\Core\Ajax\AjaxResponse::ajaxRender() and sent to the browser.
- *   - The browser unserializes the returned JSON string into an array of
- *     command objects and executes each command, resulting in the old page
- *     content within and including the HTML element specified by
- *     #ajax['wrapper'] being replaced by the new content returned by
- *     #ajax['callback'], using a JavaScript animation effect specified by
- *     #ajax['effect'].
+ * @section sec_framework Ajax responses in forms
+ * Forms that use the Drupal Form API (see the
+ * @link form_api Form API topic @endlink for more information about forms) can
+ * trigger AJAX responses. Here is an outline of the steps:
+ * - Add property '#ajax' to a form element in your form array, to trigger an
+ *   Ajax response.
+ * - Write an Ajax callback to process the input and respond.
+ * See sections below for details on these two steps.
  *
- * A simple example of basic Ajax use from the
- * @link http://drupal.org/project/examples Examples module @endlink follows:
+ * @subsection sub_form Adding Ajax triggers to a form
+ * As an example of adding Ajax triggers to a form, consider editing a date
+ * format, where the user is provided with a sample of the generated date output
+ * as they type. To accomplish this, typing in the text field should trigger an
+ * Ajax response. This is done in the text field form array element
+ * in \Drupal\config_translation\FormElement\DateFormat::getFormElement():
  * @code
- * function main_page() {
- *   return \Drupal::formBuilder()->getForm('ajax_example_simplest');
- * }
- *
- * function ajax_example_simplest($form, FormStateInterface $form_state) {
- *   $form = array();
- *   $form['changethis'] = array(
- *     '#type' => 'select',
- *     '#options' => array(
- *       'one' => 'one',
- *       'two' => 'two',
- *       'three' => 'three',
- *     ),
- *     '#ajax' => array(
- *       'callback' => 'ajax_example_simplest_callback',
- *       'wrapper' => 'replace_textfield_div',
- *      ),
- *   );
- *
- *   // This entire form element will be replaced with an updated value.
- *   $form['replace_textfield'] = array(
- *     '#type' => 'textfield',
- *     '#title' => t("The default value will be changed"),
- *     '#description' => t("Say something about why you chose") . "'" .
- *       (!empty($form_state['values']['changethis'])
- *       ? $form_state['values']['changethis'] : t("Not changed yet")) . "'",
- *     '#prefix' => '<div id="replace_textfield_div">',
- *     '#suffix' => '</div>',
- *   );
- *   return $form;
- * }
- *
- * function ajax_example_simplest_callback($form, FormStateInterface $form_state) {
- *   // The form has already been submitted and updated. We can return the replaced
- *   // item as it is.
- *   return $form['replace_textfield'];
- * }
+ * '#ajax' => array(
+ *   'callback' => 'Drupal\config_translation\FormElement\DateFormat::ajaxSample',
+ *   'event' => 'keyup',
+ *   'progress' => array(
+ *     'type' => 'throbber',
+ *     'message' => NULL,
+ *   ),
+ * ),
  * @endcode
  *
- * In the above example, the 'changethis' element is Ajax-enabled. The default
- * #ajax['event'] is 'change', so when the 'changethis' element changes,
- * an Ajax call is made. The form is submitted and reprocessed, and then the
- * callback is called. In this case, the form has been automatically
- * built changing $form['replace_textfield']['#description'], so the callback
- * just returns that part of the form.
- *
- * To implement Ajax handling in a form, add '#ajax' to the form
- * definition of a field. That field will trigger an Ajax event when it is
- * clicked (or changed, depending on the kind of field). #ajax supports
- * the following parameters (either 'path' or 'callback' is required at least):
- * - #ajax['callback']: The callback to invoke to handle the server side of the
- *   Ajax event, which will receive a $form and $form_state as arguments, and
- *   returns a renderable array (most often a form or form fragment), an HTML
- *   string, or an array of Ajax commands. If returning a renderable array or
- *   a string, the value will replace the original element named in
- *   #ajax['wrapper'], and
- *   theme_status_messages()
- *   will be prepended to that
- *   element. (If the status messages are not wanted, return an array
- *   of Ajax commands instead.)
- *   #ajax['wrapper']. If an array of Ajax commands is returned, it will be
- *   executed by the calling code.
- * - #ajax['path']: The menu path to use for the request. This is often omitted
- *   and the default is used. This path should map
- *   to a controller that returns data using
- *   \Drupal\Core\Ajax\AjaxResponse::ajaxRender(). Defaults to 'system/ajax',
- *   which invokes \Drupal\system\FormAjaxController::content(), eventually
- *   calling the function named in #ajax['callback']. If you use a custom path,
- *   you must set up the menu entry and handle the entire callback in your own
- *   code.
- * - #ajax['wrapper']: The CSS ID of the area to be replaced by the content
- *   returned by the #ajax['callback'] function. The content returned from
- *   the callback will replace the entire element named by #ajax['wrapper'].
- *   The wrapper is usually created using #prefix and #suffix properties in the
- *   form. Note that this is the wrapper ID, not a CSS selector. So to replace
- *   the element referred to by the CSS selector #some-selector on the page,
- *   use #ajax['wrapper'] = 'some-selector', not '#some-selector'.
- * - #ajax['effect']: The jQuery effect to use when placing the new HTML.
- *   Defaults to no effect. Valid options are 'none', 'slide', or 'fade'.
- * - #ajax['speed']: The effect speed to use. Defaults to 'slow'. May be
- *   'slow', 'fast' or a number in milliseconds which represents the length
- *   of time the effect should run.
- * - #ajax['event']: The JavaScript event to respond to. This is normally
- *   selected automatically for the type of form widget being used, and
- *   is only needed if you need to override the default behavior.
- * - #ajax['prevent']: A JavaScript event to prevent when 'event' is triggered.
- *   Defaults to 'click' for #ajax on #type 'submit', 'button', and
- *   'image_button'. Multiple events may be specified separated by spaces.
- *   For example, when binding #ajax behaviors to form buttons, pressing the
- *   ENTER key within a textfield triggers the 'click' event of the form's first
- *   submit button. Triggering Ajax in this situation leads to problems, like
- *   breaking autocomplete textfields. Because of that, Ajax behaviors are bound
- *   to the 'mousedown' event on form buttons by default. However, binding to
- *   'mousedown' rather than 'click' means that it is possible to trigger a
- *   click by pressing the mouse, holding the mouse button down until the Ajax
- *   request is complete and the button is re-enabled, and then releasing the
- *   mouse button. For this case, 'prevent' can be set to 'click', so an
- *   additional event handler is bound to prevent such a click from triggering a
- *   non-Ajax form submission. This also prevents a textfield's ENTER press
- *   triggering a button's non-Ajax form submission behavior.
- * - #ajax['method']: The jQuery method to use to place the new HTML.
- *   Defaults to 'replaceWith'. May be: 'replaceWith', 'append', 'prepend',
- *   'before', 'after', or 'html'. See the
- *   @link http://api.jquery.com/category/manipulation/ jQuery manipulators documentation @endlink
- *   for more information on these methods.
- * - #ajax['progress']: Choose either a throbber or progress bar that is
- *   displayed while awaiting a response from the callback, and add an optional
- *   message. Possible keys: 'type', 'message', 'url', 'interval'.
- *   More information is available in the
- *   @link forms_api_reference.html Form API Reference @endlink
- *
- * In addition to using Form API for doing in-form modification, Ajax may be
- * enabled by adding classes to buttons and links. By adding the 'use-ajax'
- * class to a link, the link will be loaded via an Ajax call. When using this
- * method, the href of the link can contain '/nojs/' as part of the path. When
- * the Ajax framework makes the request, it will convert this to '/ajax/'.
- * The server is then able to easily tell if this request was made through an
- * actual Ajax request or in a degraded state, and respond appropriately.
+ * As you can see from this example, the #ajax property for a form element is
+ * an array. Here are the details of its elements, all of which are optional:
+ * - callback: The callback to invoke to handle the server side of the
+ *   Ajax event. More information on callbacks is below in @ref sub_callback.
+ * - path: The URL path to use for the request. If omitted, defaults to
+ *   'system/ajax', which invokes the default Drupal Ajax processing (this will
+ *   call the callback supplied in the 'callback' element). If you supply a
+ *   path, you must set up a routing entry to handle the request yourself and
+ *   return output described in @ref sub_callback below. See the
+ *   @link menu Routing topic @endlink for more information on routing.
+ * - wrapper: The HTML 'id' attribute of the area where the content returned by
+ *   the callback should be placed. Note that callbacks have a choice of
+ *   returning content or JavaScript commands; 'wrapper' is used for content
+ *   returns.
+ * - method: The jQuery method for placing the new content (used with
+ *   'wrapper'). Valid options are 'replaceWith' (default), 'append', 'prepend',
+ *   'before', 'after', or 'html'. See
+ *   http://api.jquery.com/category/manipulation/ for more information on these
+ *   methods.
+ * - effect: The jQuery effect to use when placing the new HTML (used with
+ *   'wrapper'). Valid options are 'none' (default), 'slide', or 'fade'.
+ * - speed: The effect speed to use (used with 'effect' and 'wrapper'). Valid
+ *   options are 'slow' (default), 'fast', or the number of milliseconds the
+ *   effect should run.
+ * - event: The JavaScript event to respond to. This is selected automatically
+ *   for the type of form element; provide a value to override the default.
+ * - prevent: A JavaScript event to prevent when the event is triggered. For
+ *   example, if you use event 'mousedown' on a button, you might want to
+ *   prevent 'click' events from also being triggered.
+ * - progress: An array indicating how to show Ajax processing progress. Can
+ *   contain one or more of these elements:
+ *   - type: Type of indicator: 'throbber' (default) or 'bar'.
+ *   - message: Translated message to display.
+ *   - url: For a bar progress indicator, URL path for determining progress.
+ *   - interval: For a bar progress indicator, how often to update it.
  *
- * Similarly, submit buttons can be given the class 'use-ajax-submit'. The
- * form will then be submitted via Ajax to the path specified in the #action.
- * Like the ajax-submit class above, this path will have '/nojs/' replaced with
- * '/ajax/' so that the submit handler can tell if the form was submitted
- * in a degraded state or not.
- *
- * As a developer you basically create a \Drupal\Core\Ajax\AjaxResponse and add
- * a couple of \Drupal\Core\Ajax\CommandInterface onto it, which will be
- * converted to a commands array automatically. This commands array will be
- * converted to a JSON object and returned to the client, which will then
- * iterate over the array and process it like a macro language.
+ * @subsection sub_callback Setting up a callback to process Ajax
+ * Once you have set up your form to trigger an Ajax response (see @ref sub_form
+ * above), you need to write some PHP code to process the response. If you use
+ * 'path' in your Ajax set-up, your route controller will be triggered with only
+ * the information you provide in the URL. If you use 'callback', your callback
+ * method is a function, which will receive the $form and $form_state from the
+ * triggering form. You can use $form_state to get information about the
+ * data the user has entered into the form. For instance, in the above example
+ * for the date format preview,
+ * \Drupal\config_translation\FormElement\DateFormat\ajaxSample() does this to
+ * get the format string entered by the user:
+ * @code
+ * $format_value = \Drupal\Component\Utility\NestedArray::getValue(
+ *   $form_state['values'],
+ *   $form_state['triggering_element']['#array_parents']);
+ * @endcode
  *
- * Each command item is an associative array which will be converted to a
- * command object on the JavaScript side. $command_item['command'] is the type
- * of command, e.g. 'alert' or 'replace', and will correspond to a method in the
- * Drupal.ajax[command] space. The command array may contain any other data that
- * the command needs to process, e.g. 'method', 'selector', 'settings', etc.
+ * Once you have processed the input, you have your choice of returning HTML
+ * markup or a set of Ajax commands. If you choose to return HTML markup, you
+ * can return it as a string or a renderable array, and it will be placed in
+ * the defined 'wrapper' element (see documentation above in @ref sub_form).
+ * In addition, any messages returned by drupal_get_messages(), themed as in
+ * status-messages.html.twig, will be prepended.
  *
- * Commands are usually created with a couple of helper functions, so they
- * look like this:
+ * To return commands, you need to set up an object of class
+ * \Drupal\Core\Ajax\AjaxResponse, and then use its addCommand() method to add
+ * individual commands to it. In the date format preview example, the format
+ * output is calculated, and then it is returned as replacement markup for a div
+ * like this:
  * @code
- *   $commands = array();
- *   // Replace the content of '#object-1' on the page with 'some html here'.
- *   $commands[] = ajax_command_replace('#object-1', 'some html here');
- *   // Add a visual "changed" marker to the '#object-1' element.
- *   $commands[] = ajax_command_changed('#object-1');
- *   // #ajax['callback'] functions are supposed to return render arrays. If
- *   // returning an Ajax commands array, it must be encapsulated in a render
- *   // array structure.
- *   return array('#type' => 'ajax', '#commands' => $commands);
+ * $response = new AjaxResponse();
+ * $response->addCommand(new ReplaceCommand(
+ *   '#edit-date-format-suffix',
+ *   '<small id="edit-date-format-suffix">' . $format . '</small>'));
+ * return $response;
  * @endcode
  *
- * When returning an Ajax command array, it is often useful to have
- * status messages rendered along with other tasks in the command array.
- * In that case the the Ajax commands array may be constructed like this:
+ * The individual commands that you can return implement interface
+ * \Drupal\Core\Ajax\CommandInterface. Available commands provide the ability
+ * to pop up alerts, manipulate text and markup in various ways, redirect
+ * to a new URL, and the generic \Drupal\Core\Ajax\InvokeCommand, which
+ * invokes an arbitrary jQuery commnd.
+ *
+ * As noted above, status messages are prepended automatically if you use the
+ * 'wrapper' method and return HTML markup. This is not the case if you return
+ * commands, but if you would like to show status messages, you can add
  * @code
- *   $commands = array();
- *   $commands[] = ajax_command_replace(NULL, $output);
- *   $status_messages = array('#theme' => 'status_messages');
- *   $commands[] = ajax_command_prepend(NULL, drupal_render($status_messages));
- *   return array('#type' => 'ajax', '#commands' => $commands);
+ * array('#theme' => 'status_messages')
  * @endcode
+ * to a render array, use drupal_render() to render it, and add a command to
+ * place the messages in an appropriate location.
  *
- * See @link ajax_commands Ajax framework commands @endlink
+ * @section sec_other Other methods for triggering Ajax
+ * Here are some additional methods you can use to trigger Ajax responses in
+ * Drupal:
+ * - Add class 'use-ajax' to a link. The link will be loaded using an Ajax
+ *   call. When using this method, the href of the link can contain '/nojs/' as
+ *   part of the path. When the Ajax JavaScript processes the page, it will
+ *   convert this to '/ajax/'. The server is then able to easily tell if this
+ *   request was made through an actual Ajax request or in a degraded state, and
+ *   respond appropriately.
+ * - Add class 'use-ajax-submit' to a submit button in a form. The form will
+ *   then be submitted via Ajax to the path specified in the #action.  Like the
+ *   ajax-submit class on links, this path will have '/nojs/' replaced with
+ *   '/ajax/' so that the submit handler can tell if the form was submitted in a
+ *   degraded state or not.
+ * - Add property '#autocomplete_route_name' to a text field in a form. The
+ *   route controller for this route must return an array of options for
+ *   autocomplete, as a \Symfony\Component\HttpFoundation\JsonResponse object.
+ *   See the @link menu Routing topic @endlink for more information about
+ *   routing.
  */
 
 /**
diff --git a/core/lib/Drupal/Core/Ajax/AddCssCommand.php b/core/lib/Drupal/Core/Ajax/AddCssCommand.php
index d28a4b5..ccd6312 100644
--- a/core/lib/Drupal/Core/Ajax/AddCssCommand.php
+++ b/core/lib/Drupal/Core/Ajax/AddCssCommand.php
@@ -16,6 +16,8 @@
  * defined in misc/ajax.js.
  *
  * @see misc/ajax.js
+ *
+ * @ingroup ajax
  */
 class AddCssCommand implements CommandInterface {
 
diff --git a/core/lib/Drupal/Core/Ajax/AfterCommand.php b/core/lib/Drupal/Core/Ajax/AfterCommand.php
index e56a92c..8674c73 100644
--- a/core/lib/Drupal/Core/Ajax/AfterCommand.php
+++ b/core/lib/Drupal/Core/Ajax/AfterCommand.php
@@ -20,6 +20,8 @@
  * defined in misc/ajax.js.
  *
  * @see http://docs.jquery.com/Manipulation/after#content
+ *
+ * @ingroup ajax
  */
 class AfterCommand extends InsertCommand {
 
diff --git a/core/lib/Drupal/Core/Ajax/AjaxResponse.php b/core/lib/Drupal/Core/Ajax/AjaxResponse.php
index 6678e7a..2ae1853 100644
--- a/core/lib/Drupal/Core/Ajax/AjaxResponse.php
+++ b/core/lib/Drupal/Core/Ajax/AjaxResponse.php
@@ -13,6 +13,8 @@
 
 /**
  * JSON response object for AJAX requests.
+ *
+ * @ingroup ajax
  */
 class AjaxResponse extends JsonResponse {
 
diff --git a/core/lib/Drupal/Core/Ajax/AlertCommand.php b/core/lib/Drupal/Core/Ajax/AlertCommand.php
index 02a96a3..325c9c2 100644
--- a/core/lib/Drupal/Core/Ajax/AlertCommand.php
+++ b/core/lib/Drupal/Core/Ajax/AlertCommand.php
@@ -11,6 +11,8 @@
 
 /**
  * AJAX command for a javascript alert box.
+ *
+ * @ingroup ajax
  */
 class AlertCommand implements CommandInterface {
 
diff --git a/core/lib/Drupal/Core/Ajax/AppendCommand.php b/core/lib/Drupal/Core/Ajax/AppendCommand.php
index cc334aa..d758720 100644
--- a/core/lib/Drupal/Core/Ajax/AppendCommand.php
+++ b/core/lib/Drupal/Core/Ajax/AppendCommand.php
@@ -20,6 +20,8 @@
  * defined in misc/ajax.js.
  *
  * @see http://docs.jquery.com/Manipulation/append#content
+ *
+ * @ingroup ajax
  */
 class AppendCommand extends InsertCommand {
 
diff --git a/core/lib/Drupal/Core/Ajax/BeforeCommand.php b/core/lib/Drupal/Core/Ajax/BeforeCommand.php
index 62b3b2f..7e3e2ea 100644
--- a/core/lib/Drupal/Core/Ajax/BeforeCommand.php
+++ b/core/lib/Drupal/Core/Ajax/BeforeCommand.php
@@ -20,6 +20,8 @@
  * defined in misc/ajax.js.
  *
  * @see http://docs.jquery.com/Manipulation/before#content
+ *
+ * @ingroup ajax
  */
 class BeforeCommand extends InsertCommand {
 
diff --git a/core/lib/Drupal/Core/Ajax/ChangedCommand.php b/core/lib/Drupal/Core/Ajax/ChangedCommand.php
index 904880d..2832d58 100644
--- a/core/lib/Drupal/Core/Ajax/ChangedCommand.php
+++ b/core/lib/Drupal/Core/Ajax/ChangedCommand.php
@@ -17,6 +17,8 @@
  *
  * This command is implemented by Drupal.AjaxCommands.prototype.changed()
  * defined in misc/ajax.js.
+ *
+ * @ingroup ajax
  */
 class ChangedCommand implements CommandInterface {
 
diff --git a/core/lib/Drupal/Core/Ajax/CloseDialogCommand.php b/core/lib/Drupal/Core/Ajax/CloseDialogCommand.php
index c5abbe0..726ff6c 100644
--- a/core/lib/Drupal/Core/Ajax/CloseDialogCommand.php
+++ b/core/lib/Drupal/Core/Ajax/CloseDialogCommand.php
@@ -9,6 +9,8 @@
 
 /**
  * Defines an AJAX command that closes the current active dialog.
+ *
+ * @ingroup ajax
  */
 class CloseDialogCommand implements CommandInterface {
 
diff --git a/core/lib/Drupal/Core/Ajax/CloseModalDialogCommand.php b/core/lib/Drupal/Core/Ajax/CloseModalDialogCommand.php
index 226dc38..46d0080 100644
--- a/core/lib/Drupal/Core/Ajax/CloseModalDialogCommand.php
+++ b/core/lib/Drupal/Core/Ajax/CloseModalDialogCommand.php
@@ -11,6 +11,8 @@
 
 /**
  * Defines an AJAX command that closes the currently visible modal dialog.
+ *
+ * @ingroup ajax
  */
 class CloseModalDialogCommand extends CloseDialogCommand {
 
diff --git a/core/lib/Drupal/Core/Ajax/CommandInterface.php b/core/lib/Drupal/Core/Ajax/CommandInterface.php
index 9de3af5..14566cf 100644
--- a/core/lib/Drupal/Core/Ajax/CommandInterface.php
+++ b/core/lib/Drupal/Core/Ajax/CommandInterface.php
@@ -12,6 +12,8 @@
  *
  * All AJAX commands passed to AjaxResponse objects should implement these
  * methods.
+ *
+ * @ingroup ajax
  */
 interface CommandInterface {
 
diff --git a/core/lib/Drupal/Core/Ajax/CssCommand.php b/core/lib/Drupal/Core/Ajax/CssCommand.php
index f878cae..470d583 100644
--- a/core/lib/Drupal/Core/Ajax/CssCommand.php
+++ b/core/lib/Drupal/Core/Ajax/CssCommand.php
@@ -19,6 +19,8 @@
  * in misc/ajax.js.
  *
  * @see http://docs.jquery.com/CSS/css#properties
+ *
+ * @ingroup ajax
  */
 class CssCommand implements CommandInterface {
 
diff --git a/core/lib/Drupal/Core/Ajax/DataCommand.php b/core/lib/Drupal/Core/Ajax/DataCommand.php
index e7e8dbf..262649d 100644
--- a/core/lib/Drupal/Core/Ajax/DataCommand.php
+++ b/core/lib/Drupal/Core/Ajax/DataCommand.php
@@ -17,6 +17,8 @@
  *
  * This command is implemented by Drupal.AjaxCommands.prototype.data() defined
  * in misc/ajax.js.
+ *
+ * @ingroup ajax
  */
 class DataCommand implements CommandInterface {
 
diff --git a/core/lib/Drupal/Core/Ajax/HtmlCommand.php b/core/lib/Drupal/Core/Ajax/HtmlCommand.php
index 3e26f03..b9c9568 100644
--- a/core/lib/Drupal/Core/Ajax/HtmlCommand.php
+++ b/core/lib/Drupal/Core/Ajax/HtmlCommand.php
@@ -20,6 +20,8 @@
  * defined in misc/ajax.js.
  *
  * @see http://docs.jquery.com/Attributes/html#val
+ *
+ * @ingroup ajax
  */
 class HtmlCommand extends InsertCommand {
 
diff --git a/core/lib/Drupal/Core/Ajax/InsertCommand.php b/core/lib/Drupal/Core/Ajax/InsertCommand.php
index 9871ef2..d1f0133 100644
--- a/core/lib/Drupal/Core/Ajax/InsertCommand.php
+++ b/core/lib/Drupal/Core/Ajax/InsertCommand.php
@@ -18,6 +18,8 @@
  *
  * This command is implemented by Drupal.AjaxCommands.prototype.insert()
  * defined in misc/ajax.js.
+ *
+ * @ingroup ajax
  */
 class InsertCommand implements CommandInterface {
 
diff --git a/core/lib/Drupal/Core/Ajax/InvokeCommand.php b/core/lib/Drupal/Core/Ajax/InvokeCommand.php
index d04b5f5..4aa1ea1 100644
--- a/core/lib/Drupal/Core/Ajax/InvokeCommand.php
+++ b/core/lib/Drupal/Core/Ajax/InvokeCommand.php
@@ -19,6 +19,8 @@
  *
  * This command is implemented by Drupal.AjaxCommands.prototype.invoke()
  * defined in misc/ajax.js.
+ *
+ * @ingroup ajax
  */
 class InvokeCommand implements CommandInterface {
 
diff --git a/core/lib/Drupal/Core/Ajax/OpenDialogCommand.php b/core/lib/Drupal/Core/Ajax/OpenDialogCommand.php
index 4b42bf7..ad20a3f 100644
--- a/core/lib/Drupal/Core/Ajax/OpenDialogCommand.php
+++ b/core/lib/Drupal/Core/Ajax/OpenDialogCommand.php
@@ -11,6 +11,8 @@
 
 /**
  * Defines an AJAX command to open certain content in a dialog.
+ *
+ * @ingroup ajax
  */
 class OpenDialogCommand implements CommandInterface {
 
diff --git a/core/lib/Drupal/Core/Ajax/OpenModalDialogCommand.php b/core/lib/Drupal/Core/Ajax/OpenModalDialogCommand.php
index c78406e..ee785c3 100644
--- a/core/lib/Drupal/Core/Ajax/OpenModalDialogCommand.php
+++ b/core/lib/Drupal/Core/Ajax/OpenModalDialogCommand.php
@@ -11,6 +11,8 @@
 
 /**
  * Defines an AJAX command to open certain content in a dialog in a modal dialog.
+ *
+ * @ingroup ajax
  */
 class OpenModalDialogCommand extends OpenDialogCommand {
   /**
diff --git a/core/lib/Drupal/Core/Ajax/PrependCommand.php b/core/lib/Drupal/Core/Ajax/PrependCommand.php
index ccaf67a..d977197 100644
--- a/core/lib/Drupal/Core/Ajax/PrependCommand.php
+++ b/core/lib/Drupal/Core/Ajax/PrependCommand.php
@@ -20,6 +20,8 @@
  * defined in misc/ajax.js.
  *
  * @see http://docs.jquery.com/Manipulation/prepend#content
+ *
+ * @ingroup ajax
  */
 class PrependCommand extends InsertCommand {
 
diff --git a/core/lib/Drupal/Core/Ajax/RedirectCommand.php b/core/lib/Drupal/Core/Ajax/RedirectCommand.php
index 220c4c9..4b0914a 100644
--- a/core/lib/Drupal/Core/Ajax/RedirectCommand.php
+++ b/core/lib/Drupal/Core/Ajax/RedirectCommand.php
@@ -11,6 +11,8 @@
 
 /**
  * Defines an AJAX command to set the window.location, loading that URL.
+ *
+ * @ingroup ajax
  */
 class RedirectCommand implements CommandInterface {
 
diff --git a/core/lib/Drupal/Core/Ajax/RemoveCommand.php b/core/lib/Drupal/Core/Ajax/RemoveCommand.php
index dd6085f..f0e5aab 100644
--- a/core/lib/Drupal/Core/Ajax/RemoveCommand.php
+++ b/core/lib/Drupal/Core/Ajax/RemoveCommand.php
@@ -20,6 +20,8 @@
  * defined in misc/ajax.js.
  *
  * @see http://docs.jquery.com/Manipulation/remove#expr
+ *
+ * @ingroup ajax
  */
 class RemoveCommand Implements CommandInterface {
 
diff --git a/core/lib/Drupal/Core/Ajax/ReplaceCommand.php b/core/lib/Drupal/Core/Ajax/ReplaceCommand.php
index 50c39af..fb2b9e5 100644
--- a/core/lib/Drupal/Core/Ajax/ReplaceCommand.php
+++ b/core/lib/Drupal/Core/Ajax/ReplaceCommand.php
@@ -21,6 +21,8 @@
  *
  * See
  * @link http://docs.jquery.com/Manipulation/replaceWith#content jQuery replaceWith command @endlink
+ *
+ * @ingroup ajax
  */
 class ReplaceCommand extends InsertCommand {
 
diff --git a/core/lib/Drupal/Core/Ajax/RestripeCommand.php b/core/lib/Drupal/Core/Ajax/RestripeCommand.php
index 460eb50..708344c 100644
--- a/core/lib/Drupal/Core/Ajax/RestripeCommand.php
+++ b/core/lib/Drupal/Core/Ajax/RestripeCommand.php
@@ -17,6 +17,8 @@
  *
  * This command is implemented by Drupal.AjaxCommands.prototype.restripe()
  * defined in misc/ajax.js.
+ *
+ * @ingroup ajax
  */
 class RestripeCommand implements CommandInterface {
 
diff --git a/core/lib/Drupal/Core/Ajax/SetDialogOptionCommand.php b/core/lib/Drupal/Core/Ajax/SetDialogOptionCommand.php
index 088c63b..bad7e1e 100644
--- a/core/lib/Drupal/Core/Ajax/SetDialogOptionCommand.php
+++ b/core/lib/Drupal/Core/Ajax/SetDialogOptionCommand.php
@@ -9,6 +9,8 @@
 
 /**
  * Defines an AJAX command that sets jQuery UI dialog properties.
+ *
+ * @ingroup ajax
  */
 class SetDialogOptionCommand implements CommandInterface {
 
diff --git a/core/lib/Drupal/Core/Ajax/SetDialogTitleCommand.php b/core/lib/Drupal/Core/Ajax/SetDialogTitleCommand.php
index b928e1e..9a2c5ac 100644
--- a/core/lib/Drupal/Core/Ajax/SetDialogTitleCommand.php
+++ b/core/lib/Drupal/Core/Ajax/SetDialogTitleCommand.php
@@ -11,6 +11,8 @@
 
 /**
  * Defines an AJAX command that sets jQuery UI dialog properties.
+ *
+ * @ingroup ajax
  */
 class SetDialogTitleCommand extends SetDialogOptionCommand {
 
diff --git a/core/lib/Drupal/Core/Ajax/SettingsCommand.php b/core/lib/Drupal/Core/Ajax/SettingsCommand.php
index 723f05b..4f1cbe8 100644
--- a/core/lib/Drupal/Core/Ajax/SettingsCommand.php
+++ b/core/lib/Drupal/Core/Ajax/SettingsCommand.php
@@ -18,6 +18,8 @@
  *
  * This command is implemented by Drupal.AjaxCommands.prototype.settings()
  * defined in misc/ajax.js.
+ *
+ * @ingroup ajax
  */
 class SettingsCommand implements CommandInterface {