diff --git a/core/includes/form.inc b/core/includes/form.inc
index e99e6b3a814..b16053e3a34 100644
--- a/core/includes/form.inc
+++ b/core/includes/form.inc
@@ -709,25 +709,25 @@ function form_load_include(&$form_state, $type, $module, $name = NULL) {
  *   build info array so that the reference can be preserved. For example, a
  *   form builder function with the following signature:
  *   @code
- *   function mymodule_form($form, &$form_state, &$object) {
+ *   function my_module_form($form, &$form_state, &$object) {
  *   }
  *   @endcode
  *   would be called via backdrop_form_submit() as follows:
  *   @code
  *   $form_state['values'] = $my_form_values;
  *   $form_state['build_info']['args'] = array(&$object);
- *   backdrop_form_submit('mymodule_form', $form_state);
+ *   backdrop_form_submit('my_module_form', $form_state);
  *   @endcode
  * For example:
  * @code
- * // register a new user
- * $form_state = array();
- * $form_state['values']['name'] = 'new-user';
- * $form_state['values']['mail'] = 'new.user@example.com';
- * $form_state['values']['pass']['pass1'] = 'password';
- * $form_state['values']['pass']['pass2'] = 'password';
- * $form_state['values']['op'] = t('Create new account');
- * backdrop_form_submit('user_register_form', $form_state);
+ *   // Register a new user.
+ *   $form_state = array();
+ *   $form_state['values']['name'] = 'new-user';
+ *   $form_state['values']['mail'] = 'new.user@example.com';
+ *   $form_state['values']['pass']['pass1'] = 'password';
+ *   $form_state['values']['pass']['pass2'] = 'password';
+ *   $form_state['values']['op'] = t('Create new account');
+ *   backdrop_form_submit('user_register_form', $form_state);
  * @endcode
  */
 function backdrop_form_submit($form_id, &$form_state) {
diff --git a/core/includes/language.inc b/core/includes/language.inc
index 8eb67d9bab4..72a091e36fa 100644
--- a/core/includes/language.inc
+++ b/core/includes/language.inc
@@ -44,7 +44,7 @@ define('LANGUAGE_NEGOTIATION_DEFAULT', 'language-default');
  * language (which by default inherits the interface language's values)
  * configurable:
  * @code
- * function mymodule_language_types_info_alter(&$language_types) {
+ * function my_module_language_types_info_alter(&$language_types) {
  *   unset($language_types[LANGUAGE_TYPE_CONTENT]['fixed']);
  * }
  * @endcode
@@ -74,13 +74,13 @@ define('LANGUAGE_NEGOTIATION_DEFAULT', 'language-default');
  * hook_language_negotiation_info_alter(). Here is an example snippet that lets
  * path prefixes be ignored for administrative paths:
  * @code
- * function mymodule_language_negotiation_info_alter(&$negotiation_info) {
+ * function my_module_language_negotiation_info_alter(&$negotiation_info) {
  *   // Replace the core function with our own function.
- *   $negotiation_info[LANGUAGE_NEGOTIATION_URL]['callbacks']['language'] = 'mymodule_from_url';
- *   $negotiation_info[LANGUAGE_NEGOTIATION_URL]['file'] = backdrop_get_path('module', 'mymodule') . '/mymodule.module';
+ *   $negotiation_info[LANGUAGE_NEGOTIATION_URL]['callbacks']['language'] = 'my_module_from_url';
+ *   $negotiation_info[LANGUAGE_NEGOTIATION_URL]['file'] = backdrop_get_path('module', 'my_module') . '/my_module.module';
  * }
  *
- * function mymodule_from_url($languages) {
+ * function my_module_from_url($languages) {
  *   // Use the core URL language negotiation provider to get a valid language
  *   // code.
  *   $langcode = locale_language_from_url($languages);
diff --git a/core/includes/lock.inc b/core/includes/lock.inc
index 60010aee503..cae792bfdf6 100644
--- a/core/includes/lock.inc
+++ b/core/includes/lock.inc
@@ -26,11 +26,11 @@
  * name of the function performing the operation. A very simple example use of
  * this API:
  * @code
- * function mymodule_long_operation() {
- *   if (lock_acquire('mymodule_long_operation')) {
+ * function my_module_long_operation() {
+ *   if (lock_acquire('my_module_long_operation')) {
  *     // Do the long operation here.
  *     // ...
- *     lock_release('mymodule_long_operation');
+ *     lock_release('my_module_long_operation');
  *   }
  * }
  * @endcode
diff --git a/core/includes/module.inc b/core/includes/module.inc
index 5b2e29ef1c2..c9773b8563b 100644
--- a/core/includes/module.inc
+++ b/core/includes/module.inc
@@ -1049,7 +1049,7 @@ function backdrop_required_modules() {
  *     'unalterable' => $unalterable,
  *     'foo' => 'bar',
  *   );
- *   backdrop_alter('mymodule_data', $alterable1, $alterable2, $context);
+ *   backdrop_alter('my_module_data', $alterable1, $alterable2, $context);
  * @endcode
  *
  * Note that objects are always passed by reference in PHP5. If it is absolutely
@@ -1059,7 +1059,7 @@ function backdrop_required_modules() {
  *   $context = array(
  *     'unalterable_object' => clone $object,
  *   );
- *   backdrop_alter('mymodule_data', $data, $context);
+ *   backdrop_alter('my_module_data', $data, $context);
  * @endcode
  *
  * @param $type
diff --git a/core/includes/pager.inc b/core/includes/pager.inc
index 4fdd0a46eaa..b0aa30ea3db 100644
--- a/core/includes/pager.inc
+++ b/core/includes/pager.inc
@@ -55,14 +55,14 @@ function pager_find_page($element = 0) {
  * @code
  *   // First find the total number of items and initialize the pager.
  *   $where = "status = 1";
- *   $total = mymodule_select("SELECT COUNT(*) FROM data " . $where)->result();
- *   $num_per_page = config_get('mymodule.settings', 'num_per_page');
+ *   $total = my_module_select("SELECT COUNT(*) FROM data " . $where)->result();
+ *   $num_per_page = config_get('my_module.settings', 'num_per_page');
  *   $page = pager_default_initialize($total, $num_per_page);
  *
  *   // Next, retrieve and display the items for the current page.
  *   $offset = $num_per_page * $page;
- *   $result = mymodule_select("SELECT * FROM data " . $where . " LIMIT %d, %d", $offset, $num_per_page)->fetchAll();
- *   $output = theme('mymodule_results', array('result' => $result));
+ *   $result = my_module_select("SELECT * FROM data " . $where . " LIMIT %d, %d", $offset, $num_per_page)->fetchAll();
+ *   $output = theme('my_module_results', array('result' => $result));
  *
  *   // Finally, display the pager controls, and return.
  *   $output .= theme('pager');
@@ -80,9 +80,9 @@ function pager_find_page($element = 0) {
  *   // parameter corresponds to an actual page of results that will exist
  *   // within the set.
  *   $page = pager_find_page();
- *   $num_per_page = config_get('mymodule.settings', 'num_per_page');
+ *   $num_per_page = config_get('my_module.settings', 'num_per_page');
  *   $offset = $num_per_page * $page;
- *   $result = mymodule_remote_search($keywords, $offset, $num_per_page);
+ *   $result = my_module_remote_search($keywords, $offset, $num_per_page);
  *
  *   // Now that we have the total number of results, initialize the pager.
  *   pager_default_initialize($result->total, $num_per_page);
diff --git a/core/modules/.DS_Store b/core/modules/.DS_Store
new file mode 100644
index 00000000000..39bca42f2d5
Binary files /dev/null and b/core/modules/.DS_Store differ
diff --git a/core/modules/admin_bar/admin_bar.api.php b/core/modules/admin_bar/admin_bar.api.php
index 4e5d2e254be..f8256d5f151 100644
--- a/core/modules/admin_bar/admin_bar.api.php
+++ b/core/modules/admin_bar/admin_bar.api.php
@@ -75,8 +75,8 @@ function hook_admin_bar_output_build(&$content) {
     $content['menu']['menu']['myitem'] = array(
       '#title' => t('My item'),
       // #attributes are used for list items (LI).
-      '#attributes' => array('class' => array('mymodule-myitem')),
-      '#href' => 'mymodule/path',
+      '#attributes' => array('class' => array('my_module-myitem')),
+      '#href' => 'my_module/path',
       // #options are passed to l().
       '#options' => array(
         'query' => backdrop_get_destination(),
diff --git a/core/modules/ckeditor/ckeditor.api.php b/core/modules/ckeditor/ckeditor.api.php
index 73e94203673..07da7c6f149 100644
--- a/core/modules/ckeditor/ckeditor.api.php
+++ b/core/modules/ckeditor/ckeditor.api.php
@@ -80,10 +80,10 @@
  */
 function hook_ckeditor_plugins() {
   $plugins['myplugin'] = array(
-    'path' => backdrop_get_path('module', 'mymodule') . '/js/myplugin',
+    'path' => backdrop_get_path('module', 'my_module') . '/js/myplugin',
     'file' => 'plugin.js',
-    'css' => array(backdrop_get_path('module', 'mymodule') . '/css/myplugin.css'),
-    'enabled callback' => 'mymodule_myplugin_plugin_check',
+    'css' => array(backdrop_get_path('module', 'my_module') . '/css/myplugin.css'),
+    'enabled callback' => 'my_module_myplugin_plugin_check',
     'buttons' => array(
       'MyPlugin' => array(
         'label' => t('My custom button'),
@@ -113,7 +113,7 @@ function hook_ckeditor_plugins() {
  * @see hook_ckeditor_plugins()
  */
 function hook_ckeditor_plugins_alter(array &$plugins) {
-  $plugins['someplugin']['enabled callback'] = 'mymodule_someplugin_enabled_callback';
+  $plugins['someplugin']['enabled callback'] = 'my_module_someplugin_enabled_callback';
 }
 
 /**
@@ -143,7 +143,7 @@ function hook_ckeditor_plugins_alter(array &$plugins) {
  * @see _ckeditor_theme_css()
  */
 function hook_ckeditor_css_alter(array &$css, $format) {
-  $css[] = backdrop_get_path('module', 'mymodule') . '/css/mymodule-ckeditor.css';
+  $css[] = backdrop_get_path('module', 'my_module') . '/css/my_module-ckeditor.css';
 }
 
 /**
diff --git a/core/modules/ckeditor5/ckeditor5.api.php b/core/modules/ckeditor5/ckeditor5.api.php
index 3789bd86300..b62cd7e438c 100644
--- a/core/modules/ckeditor5/ckeditor5.api.php
+++ b/core/modules/ckeditor5/ckeditor5.api.php
@@ -72,9 +72,9 @@
  */
 function hook_ckeditor5_plugins() {
   $plugins['myPlugin.MyPlugin'] = array(
-    'library' => array('mymodule', 'mymodule.ckeditor5.myplugin'),
-    'css' => array(backdrop_get_path('module', 'mymodule') . '/css/myplugin.css'),
-    'enabled_callback' => 'mymodule_myplugin_plugin_check',
+    'library' => array('my_module', 'my_module.ckeditor5.myplugin'),
+    'css' => array(backdrop_get_path('module', 'my_module') . '/css/myplugin.css'),
+    'enabled_callback' => 'my_module_myplugin_plugin_check',
     'buttons' => array(
       'myButton' => array(
         'library' => array('my_module', 'my-module-ckeditor5-plugin'),
@@ -101,7 +101,7 @@ function hook_ckeditor5_plugins() {
  * @see hook_ckeditor5_plugins()
  */
 function hook_ckeditor5_plugins_alter(array &$plugins) {
-  $plugins['someplugin']['enabled callback'] = 'mymodule_someplugin_enabled_callback';
+  $plugins['someplugin']['enabled callback'] = 'my_module_someplugin_enabled_callback';
 }
 
 /**
@@ -139,7 +139,7 @@ function hook_ckeditor5_plugins_alter(array &$plugins) {
  * @see _ckeditor5_theme_css()
  */
 function hook_ckeditor5_css_alter(array &$css) {
-  $css[] = backdrop_get_path('module', 'mymodule') . '/css/mymodule-ckeditor5.css';
+  $css[] = backdrop_get_path('module', 'my_module') . '/css/my_module-ckeditor5.css';
 }
 
 /**
diff --git a/core/modules/config/config.api.php b/core/modules/config/config.api.php
index 63b6657ad39..f7f87bf12f0 100644
--- a/core/modules/config/config.api.php
+++ b/core/modules/config/config.api.php
@@ -62,7 +62,7 @@ function hook_config_info() {
  * @throws ConfigValidateException
  */
 function hook_config_data_validate(Config $config, array $config_info) {
-  if ($config->getName() === 'mymodule.settings') {
+  if ($config->getName() === 'my_module.settings') {
     if (!module_exists($config->get('module'))) {
       throw new ConfigValidateException(t('The configuration "@file" could not be imported because the module "@module" is not enabled.', array('@file' => $config->getName(), '@module' => $config->get('module'))));
     }
@@ -87,7 +87,7 @@ function hook_config_data_validate(Config $config, array $config_info) {
  * @throws ConfigValidateException
  */
 function hook_config_create_validate(Config $staging_config, $all_changes) {
-  if ($staging_config->getName() === 'mymodule.settings') {
+  if ($staging_config->getName() === 'my_module.settings') {
     // Ensure that the name key is no longer than 64 characters.
     if (strlen($staging_config->get('name')) > 64) {
       throw new ConfigValidateException(t('The configuration "@file" must have a "name" attribute less than 64 characters.', array('@file' => $staging_config->getName())));
@@ -115,7 +115,7 @@ function hook_config_create_validate(Config $staging_config, $all_changes) {
  * @throws ConfigValidateException
  */
 function hook_config_update_validate(Config $staging_config, Config $active_config, $all_changes) {
-  if ($staging_config->getName() === 'mymodule.settings') {
+  if ($staging_config->getName() === 'my_module.settings') {
     // Ensure that the name key is no longer than 64 characters.
     if (strlen($staging_config->get('name')) > 64) {
       throw new ConfigValidateException(t('The configuration "@file" must have a "name" attribute less than 64 characters.', array('@file' => $staging_config->getName())));
@@ -143,11 +143,15 @@ function hook_config_update_validate(Config $staging_config, Config $active_conf
 function hook_config_delete_validate(Config $active_config, $all_changes) {
   if (strpos($active_config->getName(), 'image.style') === 0) {
     // Check if another configuration depends on this configuration.
-    if (!isset($all_changes['mymodule.settings']) || $all_changes['mymodule.settings'] !== 'delete') {
-      $my_config = config('mymodule.settings');
+    if (!isset($all_changes['my_module.settings']) || $all_changes['my_module.settings'] !== 'delete') {
+      $my_config = config('my_module.settings');
       $image_style_name = $active_config->get('name');
       if ($my_config->get('image_style') === $image_style_name) {
-        throw new ConfigValidateException(t('The configuration "@file" cannot be deleted because the image style "@style" is in use by "@mymodule".', array('@file' => $active_config->getName(), '@style' => $image_style_name, '@mymodule' => $my_config->getName())));
+        throw new ConfigValidateException(t('The configuration "@file" cannot be deleted because the image style "@style" is in use by "@my_module".', array(
+          '@file' => $active_config->getName(),
+          '@style' => $image_style_name,
+          '@my_module' => $my_config->getName(),
+        )));
       }
     }
   }
@@ -172,9 +176,9 @@ function hook_config_create(Config $staging_config) {
  * Respond to configuration updates.
  *
  * @param Config $staging_config
- *   The configuration object for the settings about to be saved. This object
- *   is always passed by reference and may be modified to adjust the settings
- *   that are saved.
+ *   The configuration object for the settings about to be saved. This object is
+ *   always passed by reference and may be modified to adjust the settings that
+ *   are saved.
  * @param Config $active_config
  *   The configuration object for the settings being replaced.
  */
@@ -199,7 +203,7 @@ function hook_config_update(Config $staging_config, Config $active_config) {
 function hook_config_delete(Config $active_config) {
   if (strpos($active_config->getName(), 'image.style') === 0) {
     $image_style_name = $active_config->get('name');
-    config('mymodule.image_style_addons.' . $image_style_name)->delete();
+    config('my_module.image_style_addons.' . $image_style_name)->delete();
   }
 }
 
diff --git a/core/modules/entity/entity.api.php b/core/modules/entity/entity.api.php
index 9742f07e982..315b32bdd53 100644
--- a/core/modules/entity/entity.api.php
+++ b/core/modules/entity/entity.api.php
@@ -219,7 +219,7 @@ function hook_entity_info_alter(&$entity_info) {
  */
 function hook_entity_load($entities, $type) {
   foreach ($entities as $entity) {
-    $entity->foo = mymodule_add_something($entity, $type);
+    $entity->foo = my_module_add_something($entity, $type);
   }
 }
 
@@ -379,7 +379,7 @@ function hook_entity_view($entity, $type, $view_mode, $langcode) {
   $entity->content['my_additional_field'] = array(
     '#markup' => $additional_field,
     '#weight' => 10,
-    '#theme' => 'mymodule_my_additional_field',
+    '#theme' => 'my_module_my_additional_field',
   );
 }
 
@@ -431,7 +431,7 @@ function hook_entity_view_alter(&$build, $type) {
 function hook_entity_prepare_view($entities, $type) {
   // Load a specific node into the user object to theme later.
   if ($type == 'user') {
-    $nodes = mymodule_get_user_nodes(array_keys($entities));
+    $nodes = my_module_get_user_nodes(array_keys($entities));
     foreach ($entities as $uid => $entity) {
       $entity->user_node = $nodes[$uid];
     }
diff --git a/core/modules/field/field.api.php b/core/modules/field/field.api.php
index b2b96259fef..2500ad82fb1 100644
--- a/core/modules/field/field.api.php
+++ b/core/modules/field/field.api.php
@@ -187,13 +187,13 @@ function hook_field_info_alter(&$info) {
   // Add a setting to all field types.
   foreach ($info as $field_type => $field_type_info) {
     $info[$field_type]['settings'] += array(
-      'mymodule_additional_setting' => 'default value',
+      'my_module_additional_setting' => 'default value',
     );
   }
 
   // Change the default widget for fields of type 'foo'.
   if (isset($info['foo'])) {
-    $info['foo']['default widget'] = 'mymodule_widget';
+    $info['foo']['default widget'] = 'my_module_widget';
   }
 }
 
@@ -817,7 +817,7 @@ function hook_field_widget_info() {
 function hook_field_widget_info_alter(&$info) {
   // Add a setting to a widget type.
   $info['text_textfield']['settings'] += array(
-    'mymodule_additional_setting' => 'default value',
+    'my_module_additional_setting' => 'default value',
   );
 
   // Let a new field type re-use an existing widget.
@@ -966,9 +966,9 @@ function hook_field_widget_form_alter(&$element, &$form_state, $context) {
  */
 function hook_field_widget_WIDGET_TYPE_form_alter(&$element, &$form_state, $context) {
   // Code here will only act on widgets of type WIDGET_TYPE.  For example,
-  // hook_field_widget_mymodule_autocomplete_form_alter() will only act on
-  // widgets of type 'mymodule_autocomplete'.
-  $element['#autocomplete_path'] = 'mymodule/autocomplete_path';
+  // hook_field_widget_my_module_autocomplete_form_alter() will only act on
+  // widgets of type 'my_module_autocomplete'.
+  $element['#autocomplete_path'] = 'my_module/autocomplete_path';
 }
 
 /**
@@ -1115,7 +1115,7 @@ function hook_field_formatter_info() {
 function hook_field_formatter_info_alter(&$info) {
   // Add a setting to a formatter type.
   $info['text_default']['settings'] += array(
-    'mymodule_additional_setting' => 'default value',
+    'my_module_additional_setting' => 'default value',
   );
 
   // Let a new field type re-use an existing formatter.
@@ -1241,7 +1241,7 @@ function hook_field_formatter_view($entity_type, $entity, $field, $instance, $la
       // customization.
       foreach ($items as $delta => $item) {
         $element[$delta] = array(
-          '#theme' => 'mymodule_theme_sample_field_formatter_themeable',
+          '#theme' => 'my_module_theme_sample_field_formatter_themeable',
           '#data' => $item['value'],
           '#some_setting' => $settings['some_setting'],
         );
@@ -1530,9 +1530,9 @@ function hook_field_attach_delete_revision($entity_type, $entity) {
  * @see field_purge_data()
  */
 function hook_field_attach_purge($entity_type, $entity, $field, $instance) {
-  // find the corresponding data in mymodule and purge it
+  // Find the corresponding data in my_module and purge it.
   if ($entity_type == 'node' && $field->field_name == 'my_field_name') {
-    mymodule_remove_mydata($entity->nid);
+    my_module_remove_mydata($entity->nid);
   }
 }
 
@@ -1732,7 +1732,7 @@ function hook_field_storage_info() {
 function hook_field_storage_info_alter(&$info) {
   // Add a setting to a storage type.
   $info['field_sql_storage']['settings'] += array(
-    'mymodule_additional_setting' => 'default value',
+    'my_module_additional_setting' => 'default value',
   );
 }
 
diff --git a/core/modules/filter/filter.api.php b/core/modules/filter/filter.api.php
index 7a202ca9167..b141310e96d 100644
--- a/core/modules/filter/filter.api.php
+++ b/core/modules/filter/filter.api.php
@@ -159,7 +159,7 @@ function hook_editor_info() {
       'resizeable' => TRUE,
     ),
     'file' => 'myeditor.admin.inc',
-    'library' => array('mymodule', 'myeditor'),
+    'library' => array('my_module', 'myeditor'),
     'js settings callback' => '_myeditor_js_settings',
   );
   return $editors;
@@ -593,7 +593,7 @@ function hook_editor_EDITOR_js_settings($format, $filters, $existing_settings) {
  * @see hook_filter_format_disable()
  */
 function hook_filter_format_insert($format) {
-  mymodule_cache_rebuild();
+  my_module_cache_rebuild();
 }
 
 /**
@@ -610,7 +610,7 @@ function hook_filter_format_insert($format) {
  * @see hook_filter_format_disable()
  */
 function hook_filter_format_update($format) {
-  mymodule_cache_rebuild();
+  my_module_cache_rebuild();
 }
 
 /**
@@ -623,7 +623,7 @@ function hook_filter_format_update($format) {
  * @see hook_filter_format_update()
  */
 function hook_filter_format_disable($format) {
-  mymodule_cache_rebuild();
+  my_module_cache_rebuild();
 }
 
 /**
diff --git a/core/modules/image/image.api.php b/core/modules/image/image.api.php
index b00878a6094..0ea082e9439 100644
--- a/core/modules/image/image.api.php
+++ b/core/modules/image/image.api.php
@@ -37,13 +37,13 @@
 function hook_image_effect_info() {
   $effects = array();
 
-  $effects['mymodule_resize'] = array(
+  $effects['my_module_resize'] = array(
     'label' => t('Resize'),
     'help' => t('Resize an image to an exact set of dimensions, ignoring aspect ratio.'),
-    'effect callback' => 'mymodule_resize_effect',
-    'dimensions callback' => 'mymodule_resize_dimensions',
-    'form callback' => 'mymodule_resize_form',
-    'summary theme' => 'mymodule_resize_summary',
+    'effect callback' => 'my_module_resize_effect',
+    'dimensions callback' => 'my_module_resize_dimensions',
+    'form callback' => 'my_module_resize_form',
+    'summary theme' => 'my_module_resize_summary',
   );
 
   return $effects;
@@ -59,9 +59,9 @@ function hook_image_effect_info() {
  */
 function hook_image_effect_info_alter(&$effects) {
   // Override the Image module's crop effect with more options.
-  $effects['image_crop']['effect callback'] = 'mymodule_crop_effect';
-  $effects['image_crop']['dimensions callback'] = 'mymodule_crop_dimensions';
-  $effects['image_crop']['form callback'] = 'mymodule_crop_form';
+  $effects['image_crop']['effect callback'] = 'my_module_crop_effect';
+  $effects['image_crop']['dimensions callback'] = 'my_module_crop_dimensions';
+  $effects['image_crop']['form callback'] = 'my_module_crop_form';
 }
 
 /**
@@ -77,8 +77,8 @@ function hook_image_effect_info_alter(&$effects) {
 function hook_image_style_save($style) {
   // If a module defines an image style and that style is renamed by the user
   // the module should update any references to that style.
-  if (isset($style['old_name']) && $style['old_name'] == config_get('mymodule.settings', 'image_style')) {
-     config_set('mymodule.settings', 'image_style', $style['name']);
+  if (isset($style['old_name']) && $style['old_name'] == config_get('my_module.settings', 'image_style')) {
+     config_set('my_module.settings', 'image_style', $style['name']);
   }
 }
 
@@ -96,8 +96,8 @@ function hook_image_style_save($style) {
 function hook_image_style_delete($style) {
   // Administrators can choose an optional replacement style when deleting.
   // Update the modules style variable accordingly.
-  if (isset($style['old_name']) && $style['old_name'] == config_get('mymodule.settings', 'image_style')) {
-    config_set('mymodule.settings', 'image_style', $style['name']);
+  if (isset($style['old_name']) && $style['old_name'] == config_get('my_module.settings', 'image_style')) {
+    config_set('my_module.settings', 'image_style', $style['name']);
   }
 }
 
@@ -115,7 +115,7 @@ function hook_image_style_delete($style) {
  */
 function hook_image_style_flush($style) {
   // Empty cached data that contains information about the style.
-  cache('mymodule')->flush();
+  cache('my_module')->flush();
 }
 
 /**
diff --git a/core/modules/layout/layout.api.php b/core/modules/layout/layout.api.php
index 26ca45e14b8..c3a0469ecfc 100644
--- a/core/modules/layout/layout.api.php
+++ b/core/modules/layout/layout.api.php
@@ -140,8 +140,8 @@ function hook_layout_context_info() {
  *     through hook_autoload_info().
  *   - path: Optional. Override the path to the file to be used. Ordinarily
  *     theme functions are located in a file in the module path (for example:
- *     mymodule/mymodule.theme.inc) and template files are located in a
- *     subdirectory named templates (for example: mymodule/templates/), but if
+ *     my_module/my_module.theme.inc) and template files are located in a
+ *     subdirectory named templates (for example: my_module/templates/), but if
  *     your file will not be in the default location, include it here. This
  *     path should be relative to the Backdrop root directory.
  *   - template: If specified, this theme implementation is a template, and
@@ -161,7 +161,7 @@ function hook_layout_style_info() {
     'title' => t('A new style'),
     'description' => t('An advanced style with settings.'),
     // The theme key for rendering an individual block.
-    'block theme' => 'mymodule_block',
+    'block theme' => 'my_module_block',
     // Provide a class name if this style has settings. The class should extend
     // the LayoutStyle class.
     'class' => 'MyModuleLayoutStyle',
@@ -356,7 +356,7 @@ function hook_layout_presave(Layout $layout) {
  * from the path in the router item and you will rely on the system to set the
  * context, you should set the position of the context(s) in the layout to the
  * position in the router. Example: the path in the router item is
- * mymodule/node/% and you wish to use the layout with path node/%. Then you
+ * my_module/node/% and you wish to use the layout with path node/%. Then you
  * would find the context at position 2 in the router item and set its
  *  Context::position variable to 2, so that the layout with path node/% looks
  * at position 2 to set the context for that placeholder.
@@ -589,7 +589,7 @@ function hook_block_configure($delta = '', $settings = array()) {
  */
 function hook_block_save($delta, &$edit = array()) {
   if ($delta == 'my_block_delta') {
-    config_set('mymodule.settings', 'my_global_value', $edit['my_global_value']);
+    config_set('my_module.settings', 'my_global_value', $edit['my_global_value']);
     // Remove the value so it is not saved by Layout module.
     unset($edit['my_global_value']);
   }
@@ -702,7 +702,7 @@ function hook_block_view_alter(&$data, $block) {
   // Add a theme wrapper function defined by the current module to all blocks
   // provided by the "some_module" module.
   if (is_array($data['content']) && $block->module == 'some_module') {
-    $data['content']['#theme_wrappers'][] = 'mymodule_special_block';
+    $data['content']['#theme_wrappers'][] = 'my_module_special_block';
   }
 }
 
@@ -735,10 +735,10 @@ function hook_block_view_alter(&$data, $block) {
  */
 function hook_block_view_MODULE_DELTA_alter(&$data, $block) {
   // This code will only run for a specific block. For example, if MODULE_DELTA
-  // in the function definition above is set to "mymodule_some_delta", the code
-  // will only run on the "some_delta" block provided by the "mymodule" module.
-
-  // Change the title of the "some_delta" block provided by the "mymodule"
+  // in the function definition above is set to "my_module_some_delta", the code
+  // will only run on the "some_delta" block provided by the "my_module" module.
+  //
+  // Change the title of the "some_delta" block provided by the "my_module"
   // module.
   $data['title'] = t('New title of the block');
 }
diff --git a/core/modules/node/node.api.php b/core/modules/node/node.api.php
index f650256fde9..6d0798ef51a 100644
--- a/core/modules/node/node.api.php
+++ b/core/modules/node/node.api.php
@@ -20,8 +20,8 @@
  * node operation:
  * - Node-type-specific hooks: When defining a node type, node_type_save()
  *   returns a 'base' component. Node-type-specific hooks are named
- *   base_hookname() instead of mymodule_hookname() (in a module called
- *   'mymodule' for example). Only the node type's corresponding implementation
+ *   base_hookname() instead of my_module_hookname() (in a module called
+ *   'my_module' for example). Only the node type's corresponding implementation
  *   is invoked. For example, book_node_info() in book.module defines the base
  *   for the 'book' node type as 'book'. So when a book node is created,
  *   hook_insert() is invoked on book_insert() only. Hooks that are
@@ -780,7 +780,7 @@ function hook_node_view(Node $node, $view_mode, $langcode) {
   $node->content['my_additional_field'] = array(
     '#markup' => $additional_field,
     '#weight' => 10,
-    '#theme' => 'mymodule_my_additional_field',
+    '#theme' => 'my_module_my_additional_field',
   );
 }
 
@@ -1014,8 +1014,8 @@ function hook_delete(Node $node) {
  * @ingroup node_api_hooks
  */
 function hook_prepare(Node $node) {
-  if (!isset($node->mymodule_value)) {
-    $node->mymodule_value = 'foo';
+  if (!isset($node->my_module_value)) {
+    $node->my_module_value = 'foo';
   }
 }
 
@@ -1247,7 +1247,7 @@ function hook_view(Node $node, $view_mode) {
   }
 
   $node->content['myfield'] = array(
-    '#markup' => theme('mymodule_myfield', $node->myfield),
+    '#markup' => theme('my_module_myfield', $node->myfield),
     '#weight' => 1,
   );
 
diff --git a/core/modules/search/search.module b/core/modules/search/search.module
index 9dc45844f13..0d60ff15a0d 100644
--- a/core/modules/search/search.module
+++ b/core/modules/search/search.module
@@ -991,8 +991,8 @@ function search_expression_insert($expression, $option, $value = NULL) {
  *
  * If your module needs to provide a more complicated search form, then you need
  * to implement it yourself without hook_search_info(). In that case, you should
- * define it as a local task (tab) under the /search page (e.g. /search/mymodule)
- * so that users know where to find it.
+ * define it as a local task (tab) under the /search page (e.g.
+ * /search/my_module), so that users know where to find it.
  */
 
 /**
diff --git a/core/modules/system/system.api.php b/core/modules/system/system.api.php
index cc13eed9d9c..616a290fdde 100644
--- a/core/modules/system/system.api.php
+++ b/core/modules/system/system.api.php
@@ -80,8 +80,8 @@ function hook_hook_info_alter(&$hooks) {
  */
 function hook_admin_paths() {
   $paths = array(
-    'mymodule/*/add' => TRUE,
-    'mymodule/*/edit' => TRUE,
+    'my_module/*/add' => TRUE,
+    'my_module/*/edit' => TRUE,
   );
   return $paths;
 }
@@ -460,7 +460,7 @@ function hook_menu_get_item_alter(&$router_item, $path, $original_map) {
   // When retrieving the router item for the current path...
   if ($path == $_GET['q']) {
     // ...call a function that prepares something for this request.
-    mymodule_prepare_something();
+    my_module_prepare_something();
   }
 }
 
@@ -485,14 +485,14 @@ function hook_menu_get_item_alter(&$router_item, $path, $original_map) {
  * components are passed to the callback function. For example, your module
  * could register path 'abc/def':
  * @code
- *   function mymodule_menu() {
+ *   function my_module_menu() {
  *     $items['abc/def'] = array(
- *       'page callback' => 'mymodule_abc_view',
+ *       'page callback' => 'my_module_abc_view',
  *     );
  *     return $items;
  *   }
  *
- *   function mymodule_abc_view($ghi = 0, $jkl = '') {
+ *   function my_module_abc_view($ghi = 0, $jkl = '') {
  *     // ...
  *   }
  * @endcode
@@ -517,9 +517,9 @@ function hook_menu_get_item_alter(&$router_item, $path, $original_map) {
  * allows you to re-use a callback function for several different paths. For
  * example:
  * @code
- *   function mymodule_menu() {
+ *   function my_module_menu() {
  *     $items['abc/def'] = array(
- *       'page callback' => 'mymodule_abc_view',
+ *       'page callback' => 'my_module_abc_view',
  *       'page arguments' => array(1, 'foo'),
  *     );
  *     return $items;
@@ -532,14 +532,14 @@ function hook_menu_get_item_alter(&$router_item, $path, $original_map) {
  * requested with optional path arguments, then the list array's arguments are
  * passed to the callback function first, followed by the optional path
  * arguments. Using the above example, when path 'abc/def/bar/baz' is requested,
- * mymodule_abc_view() will be called with 'def', 'foo', 'bar' and 'baz' as
+ * my_module_abc_view() will be called with 'def', 'foo', 'bar' and 'baz' as
  * arguments, in that order.
  *
  * Special care should be taken for the page callback backdrop_get_form(),
  * because your specific form callback function will always receive $form and
  * &$form_state as the first function arguments:
  * @code
- *   function mymodule_abc_form($form, &$form_state) {
+ *   function my_module_abc_form($form, &$form_state) {
  *     // ...
  *     return $form;
  *   }
@@ -552,7 +552,7 @@ function hook_menu_get_item_alter(&$router_item, $path, $original_map) {
  * your module could register path 'my-module/%/edit':
  * @code
  *   $items['my-module/%/edit'] = array(
- *     'page callback' => 'mymodule_abc_edit',
+ *     'page callback' => 'my_module_abc_edit',
  *     'page arguments' => array(1),
  *   );
  * @endcode
@@ -562,30 +562,30 @@ function hook_menu_get_item_alter(&$router_item, $path, $original_map) {
  *
  * @subsection sub_autoload_wildcards Auto-Loader Wildcards
  * Registered paths may also contain special "auto-loader" wildcard components
- * in the form of '%mymodule_abc', where the '%' part means that this path
- * component is a wildcard, and the 'mymodule_abc' part defines the prefix for a
- * load function, which here would be named mymodule_abc_load(). When a matching
- * path is requested, your load function will receive as its first argument the
- * path component in the position of the wildcard; load functions may also be
- * passed additional arguments (see "load arguments" in the return value
- * section below). For example, your module could register path
- * 'my-module/%mymodule_abc/edit':
+ * in the form of '%my_module_abc', where the '%' part means that this path
+ * component is a wildcard, and the 'my_module_abc' part defines the prefix for
+ * a load function, which here would be named my_module_abc_load(). When a
+ * matching path is requested, your load function will receive as its first
+ * argument the path component in the position of the wildcard; load functions
+ * may also be passed additional arguments (see "load arguments" in the return
+ * value section below). For example, your module could register path
+ * 'my-module/%my_module_abc/edit':
  * @code
- *   $items['my-module/%mymodule_abc/edit'] = array(
- *     'page callback' => 'mymodule_abc_edit',
+ *   $items['my-module/%my_module_abc/edit'] = array(
+ *     'page callback' => 'my_module_abc_edit',
  *     'page arguments' => array(1),
  *   );
  * @endcode
  * When path 'my-module/123/edit' is requested, your load function
- * mymodule_abc_load() will be invoked with the argument '123', and should
+ * my_module_abc_load() will be invoked with the argument '123', and should
  * load and return an "abc" object with internal id 123:
  * @code
- *   function mymodule_abc_load($abc_id) {
- *     return db_query("SELECT * FROM {mymodule_abc} WHERE abc_id = :abc_id", array(':abc_id' => $abc_id))->fetchObject();
+ *   function my_module_abc_load($abc_id) {
+ *     return db_query("SELECT * FROM {my_module_abc} WHERE abc_id = :abc_id", array(':abc_id' => $abc_id))->fetchObject();
  *   }
  * @endcode
  * This 'abc' object will then be passed into the callback functions defined
- * for the menu item, such as the page callback function mymodule_abc_edit()
+ * for the menu item, such as the page callback function my_module_abc_edit()
  * to replace the integer 1 in the argument array. Note that a load function
  * should return FALSE when it is unable to provide a loadable object. For
  * example, the node_load() function for the 'node/%node/edit' menu item will
@@ -594,7 +594,7 @@ function hook_menu_get_item_alter(&$router_item, $path, $original_map) {
  *
  * @subsection sub_argument_wildcards Argument Wildcards
  * You can also define a %wildcard_to_arg() function (for the example menu
- * entry above this would be 'mymodule_abc_to_arg()'). The _to_arg() function
+ * entry above this would be 'my_module_abc_to_arg()'). The _to_arg() function
  * is invoked to retrieve a value that is used in the path in place of the
  * wildcard. A good example is user.module, which defines
  * user_uid_optional_to_arg() (corresponding to the menu entry
@@ -1305,34 +1305,34 @@ function hook_form_BASE_FORM_ID_alter(&$form, &$form_state, $form_id) {
  *     belong to the wizard, which all share the same wrapper callback.
  */
 function hook_forms($form_id, $args) {
-  // Reroute the (non-existing) $form_id 'mymodule_first_form' to
-  // 'mymodule_main_form'.
-  $forms['mymodule_first_form'] = array(
-    'callback' => 'mymodule_main_form',
+  // Reroute the (non-existing) $form_id 'my_module_first_form' to
+  // 'my_module_main_form'.
+  $forms['my_module_first_form'] = array(
+    'callback' => 'my_module_main_form',
   );
 
   // Reroute the $form_id and prepend an additional argument that gets passed to
-  // the 'mymodule_main_form' form builder function.
-  $forms['mymodule_second_form'] = array(
-    'callback' => 'mymodule_main_form',
+  // the 'my_module_main_form' form builder function.
+  $forms['my_module_second_form'] = array(
+    'callback' => 'my_module_main_form',
     'callback arguments' => array('some parameter'),
   );
 
   // Reroute the $form_id, but invoke the form builder function
-  // 'mymodule_main_form_wrapper' first, so we can prepopulate the $form array
-  // that is passed to the actual form builder 'mymodule_main_form'.
-  $forms['mymodule_wrapped_form'] = array(
-    'callback' => 'mymodule_main_form',
-    'wrapper_callback' => 'mymodule_main_form_wrapper',
+  // 'my_module_main_form_wrapper' first, so we can prepopulate the $form array
+  // that is passed to the actual form builder 'my_module_main_form'.
+  $forms['my_module_wrapped_form'] = array(
+    'callback' => 'my_module_main_form',
+    'wrapper_callback' => 'my_module_main_form_wrapper',
   );
 
   // Build a form with a static class callback.
-  $forms['mymodule_class_generated_form'] = array(
+  $forms['my_module_class_generated_form'] = array(
     // This will call: MyClass::generateMainForm().
     'callback' => array('MyClass', 'generateMainForm'),
     // The base_form_id is required when the callback is a static function in
     // a class. This can also be used to keep newer code backwards compatible.
-    'base_form_id' => 'mymodule_main_form',
+    'base_form_id' => 'my_module_main_form',
   );
 
   return $forms;
@@ -1509,7 +1509,7 @@ function hook_module_implements_alter(&$implementations, $hook) {
 /**
  * Return additional themes provided by modules.
  *
- * Only use this hook for testing purposes. Use a hidden MYMODULE_test.module
+ * Only use this hook for testing purposes. Use a hidden MY_MODULE_test.module
  * to implement this hook. Testing themes should be hidden, too.
  *
  * This hook is invoked from _system_rebuild_theme_data() and allows modules to
@@ -1521,7 +1521,7 @@ function hook_module_implements_alter(&$implementations, $hook) {
  *   is the corresponding path to the theme's .info file.
  */
 function hook_system_theme_info() {
-  $themes['mymodule_test_theme'] = backdrop_get_path('module', 'mymodule') . '/mymodule_test_theme/mymodule_test_theme.info';
+  $themes['my_module_test_theme'] = backdrop_get_path('module', 'my_module') . '/my_module_test_theme/my_module_test_theme.info';
   return $themes;
 }
 
@@ -1957,7 +1957,7 @@ function hook_flush_caches() {
  *   An array of modules about to be installed.
  */
 function hook_modules_preinstall($modules) {
-  mymodule_cache_clear();
+  my_module_cache_clear();
 }
 
 /**
@@ -1969,7 +1969,7 @@ function hook_modules_preinstall($modules) {
  *   An array of modules about to be enabled.
  */
 function hook_modules_preenable($modules) {
-  mymodule_cache_clear();
+  my_module_cache_clear();
 }
 
 /**
@@ -2014,8 +2014,8 @@ function hook_modules_installed($modules) {
  */
 function hook_modules_enabled($modules) {
   if (in_array('lousy_module', $modules)) {
-    backdrop_set_message(t('mymodule is not compatible with lousy_module'), 'error');
-    mymodule_disable_functionality();
+    backdrop_set_message(t('my_module is not compatible with lousy_module'), 'error');
+    my_module_disable_functionality();
   }
 }
 
@@ -2034,7 +2034,7 @@ function hook_modules_enabled($modules) {
  */
 function hook_modules_disabled($modules) {
   if (in_array('lousy_module', $modules)) {
-    mymodule_enable_functionality();
+    my_module_enable_functionality();
   }
 }
 
@@ -2056,11 +2056,11 @@ function hook_modules_disabled($modules) {
  */
 function hook_modules_uninstalled($modules) {
   foreach ($modules as $module) {
-    db_delete('mymodule_table')
+    db_delete('my_module_table')
       ->condition('module', $module)
       ->execute();
   }
-  mymodule_cache_rebuild();
+  my_module_cache_rebuild();
 }
 
 /**
@@ -2667,31 +2667,31 @@ function hook_schema_alter(&$schema) {
  * @ingroup schemaapi
  */
 function hook_schema_0() {
-  $schema['mymodule'] = array(
-    'description' => 'The base table for mymodule.',
+  $schema['my_module'] = array(
+    'description' => 'The base table for my_module.',
     'fields' => array(
-      'mymodule_id' => array(
-        'description' => 'The primary identifier for mymodule.',
+      'my_module_id' => array(
+        'description' => 'The primary identifier for my_module.',
         'type' => 'serial',
         'unsigned' => TRUE,
         'not null' => TRUE,
       ),
       'title' => array(
-        'description' => 'The title column of mymodule.',
+        'description' => 'The title column of my_module.',
         'type' => 'varchar',
         'length' => 255,
         'not null' => TRUE,
         'default' => '',
       ),
       'description' => array(
-        'description' => 'The description column of mymodule.',
+        'description' => 'The description column of my_module.',
         'type' => 'varchar',
         'length' => 255,
         'not null' => TRUE,
         'default' => '',
       ),
     ),
-    'primary key' => array('mymodule_id'),
+    'primary key' => array('my_module_id'),
   );
   return $schema;
 }
@@ -2816,9 +2816,10 @@ function hook_install() {
  * updates should adhere to the
  * @link http://drupal.org/node/150215 Schema API. @endlink
  *
- * Implementations of this hook should be placed in a mymodule.install file in
- * the same directory as mymodule.module. Backdrop core's updates are implemented
- * using the system module as a name and stored in database/updates.inc.
+ * Implementations of this hook should be placed in a my_module.install file in
+ * the same directory as my_module.module. Backdrop core's updates are
+ * implemented using the system module as a name and stored in
+ * database/updates.inc.
  *
  * Implementations of hook_update_N() are named (module name)_update_(number).
  * The numbers are composed of three parts:
@@ -2840,14 +2841,15 @@ function hook_install() {
  * compatibility.
  *
  * Examples:
- * - mymodule_update_1000(): This is the required update for mymodule to run
+ * - my_module_update_1000(): This is the required update for my_module to run
  *   with Backdrop core API 1.x when upgrading from Drupal core API 7.x.
- * - mymodule_update_1100(): This is the first update to get the database/config
- *   ready to run mymodule 1.x-1.*.
- * - mymodule_update_1200(): This is the first update to get the database/config
- *   ready to run mymodule 1.x-2.*. Users can directly update from Drupal 7.x to
- *   Backdrop 1.x-2.*, and they get all the 10xx and 12xx updates, but not the
- *   11xx updates, because those reside in the 1.x-1.x branch only.
+ * - my_module_update_1100(): This is the first update to get the
+ *   database/config ready to run my_module 1.x-1.*.
+ * - my_module_update_1200(): This is the first update to get the
+ *   database/config ready to run my_module 1.x-2.*. Users can directly update
+ *   from Drupal 7.x to Backdrop 1.x-2.*, and they get all the 10xx and 12xx
+ *   updates, but not the 11xx updates, because those reside in the 1.x-1.x
+ *   branch only.
  *
  * A good rule of thumb is to remove updates older than two major releases of
  * Backdrop. See hook_update_last_removed() to notify Backdrop about the
@@ -2860,12 +2862,12 @@ function hook_install() {
  *
  * Module functions not in the install file cannot be counted on to be available
  * from within a hook_update_N() function. In order to call a function from your
- * mymodule.module or an include file, you need to explicitly load that file
+ * my_module.module or an include file, you need to explicitly load that file
  * first.
  *
  * This is because if a module was previously enabled but is now disabled (and
  * has not been uninstalled), update hooks will still be called for that module
- * during system updates, but the mymodule.module file (and any other files
+ * during system updates, but the my_module.module file (and any other files
  * loaded by that one, including, for example, autoload information) will not
  * have been loaded.
  *
@@ -2905,20 +2907,21 @@ function hook_install() {
  * @see update_get_update_list()
  */
 function hook_update_N(&$sandbox) {
-  // For non-multipass updates the signature can be `function hook_update_N() {`
+  // For non-multipass updates the signature can be:
+  // `function hook_update_N() {`.
 
   // Convert Drupal 7 variables to Backdrop config. Make sure these new config
-  // settings and their default values exist in `config/mymodule.settings.json`.
-  $config = config('mymodule.settings');
-  $config->set('one', update_variable_get('mymodule_one', '1.11'));
-  $config->set('two', update_variable_get('mymodule_two', '2.22'));
+  // settings and their default values exist in config/my_module.settings.json.
+  $config = config('my_module.settings');
+  $config->set('one', update_variable_get('my_module_one', '1.11'));
+  $config->set('two', update_variable_get('my_module_two', '2.22'));
   $config->save();
-  update_variable_del('mymodule_one');
-  update_variable_del('mymodule_two');
+  update_variable_del('my_module_one');
+  update_variable_del('my_module_two');
 
   // Update existing config with a new setting. Make sure the new setting and
-  // its default value exists in `config/mymodule.settings.json`.
-  config_set('mymodule.settings', 'three', '3.33');
+  // its default value exists in `config/my_module.settings.json`.
+  config_set('my_module.settings', 'three', '3.33');
 
   // For most database updates, the following is sufficient.
   db_add_field('mytable1', 'newcol', array('type' => 'int', 'not null' => TRUE, 'description' => 'My new integer column.'));
@@ -2970,8 +2973,8 @@ function hook_update_N(&$sandbox) {
  * system to determine the appropriate order in which updates should be run, as
  * well as to search for missing dependencies.
  *
- * Implementations of this hook should be placed in a mymodule.install file in
- * the same directory as mymodule.module.
+ * Implementations of this hook should be placed in a my_module.install file in
+ * the same directory as my_module.module.
  *
  * @return
  *   A multidimensional array containing information about the module update
@@ -2988,21 +2991,21 @@ function hook_update_N(&$sandbox) {
  * @see hook_update_N()
  */
 function hook_update_dependencies() {
-  // Indicate that the mymodule_update_1000() function provided by this module
+  // Indicate that the my_module_update_1000() function provided by this module
   // must run after the another_module_update_1002() function provided by the
   // 'another_module' module.
-  $dependencies['mymodule'][1000] = array(
+  $dependencies['my_module'][1000] = array(
     'another_module' => 1002,
   );
-  // Indicate that the mymodule_update_1001() function provided by this module
+  // Indicate that the my_module_update_1001() function provided by this module
   // must run before the yet_another_module_update_1004() function provided by
   // the 'yet_another_module' module. (Note that declaring dependencies in this
   // direction should be done only in rare situations, since it can lead to the
   // following problem: If a site has already run the yet_another_module
   // module's database updates before it updates its codebase to pick up the
-  // newest mymodule code, then the dependency declared here will be ignored.)
+  // newest my_module code, then the dependency declared here will be ignored.)
   $dependencies['yet_another_module'][1004] = array(
-    'mymodule' => 1001,
+    'my_module' => 1001,
   );
   return $dependencies;
 }
@@ -3010,12 +3013,12 @@ function hook_update_dependencies() {
 /**
  * Return a number which is no longer available as hook_update_N().
  *
- * If you remove some update functions from your mymodule.install file, you
+ * If you remove some update functions from your my_module.install file, you
  * should notify Backdrop of those missing functions. This way, Backdrop can
  * ensure that no update is accidentally skipped.
  *
- * Implementations of this hook should be placed in a mymodule.install file in
- * the same directory as mymodule.module.
+ * Implementations of this hook should be placed in a my_module.install file in
+ * the same directory as my_module.module.
  *
  * If upgrading from a Drupal 7 module where the last removed update was a
  * update function numbering in the 7xxx values, that update number should still
@@ -3025,14 +3028,14 @@ function hook_update_dependencies() {
  *
  * @return int
  *   An integer, corresponding to hook_update_N() which has been removed from
- *   mymodule.install.
+ *   my_module.install.
  *
  * @see hook_update_N()
  */
 function hook_update_last_removed() {
-  // We've removed the 1.x-1.x version of mymodule, including database updates.
+  // We've removed the 1.x-1.x version of my_module, including database updates.
   // For the 1.x-2.x version of the module, the next update function would be
-  // mymodule_update_1200().
+  // my_module_update_1200().
   return 1103;
 }
 
@@ -3080,7 +3083,7 @@ function hook_uninstall() {
  * @see hook_modules_enabled()
  */
 function hook_enable() {
-  mymodule_cache_rebuild();
+  my_module_cache_rebuild();
 }
 
 /**
@@ -3094,7 +3097,7 @@ function hook_enable() {
  * @see hook_modules_disabled()
  */
 function hook_disable() {
-  mymodule_cache_rebuild();
+  my_module_cache_rebuild();
 }
 
 /**
@@ -3347,7 +3350,7 @@ function hook_html_head_alter(&$head_elements) {
   foreach ($head_elements as $key => $element) {
     if (isset($element['#attributes']['rel']) && $element['#attributes']['rel'] == 'canonical') {
       // I want a custom canonical URL.
-      $head_elements[$key]['#attributes']['href'] = mymodule_canonical_url();
+      $head_elements[$key]['#attributes']['href'] = my_module_canonical_url();
     }
   }
 }
@@ -4047,7 +4050,7 @@ function hook_filetransfer_info() {
  * @see hook_filetransfer_info()
  */
 function hook_filetransfer_info_alter(&$filetransfer_info) {
-  if (config_get('mymodule.settings', 'paranoia')) {
+  if (config_get('my_module.settings', 'paranoia')) {
     // Remove the FTP option entirely.
     unset($filetransfer_info['ftp']);
     // Make sure the SSH option is listed first.
@@ -4076,16 +4079,16 @@ function hook_filetransfer_info_alter(&$filetransfer_info) {
  * Instead, a simplified utility function should be used. If a utility version
  * of the API function you require does not already exist, then you should
  * create a new function. The new utility function should be named
- * _update_N_mymodule_my_function(). N is the schema version the function acts
+ * _update_N_my_module_my_function(). N is the schema version the function acts
  * on (the schema version is the number N from the hook_update_N()
  * implementation where this schema was introduced, or a number following the
- * same numbering scheme), and mymodule_my_function is the name of the original
+ * same numbering scheme), and my_module_my_function is the name of the original
  * API function including the module's name.
  *
  * Examples:
- * - _update_6000_mymodule_save(): This function performs a save operation
+ * - _update_6000_my_module_save(): This function performs a save operation
  *   without invoking any hooks using the 6.x schema.
- * - _update_7000_mymodule_save(): This function performs the same save
+ * - _update_7000_my_module_save(): This function performs the same save
  *   operation using the 7.x schema.
  *
  * The utility function should not invoke any hooks, and should perform database
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index 0a340732915..b37b5570797 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -4490,18 +4490,18 @@ function system_file_download($uri) {
  * submit function saves all the data in the form.
  *
  * If $form['#config'] is present in the form, the values will be saved to the
- * named settings file (e.g., mymodule.settings). If sub-elements or groups of
+ * named settings file (e.g., my_module.settings). If sub-elements or groups of
  * sub-elements have their own '#config' keys, then values of those elements and
  * their children will be saved to that settings file.
  *
  * For example, consider the form:
  *
  * @code
- * $primary_config = config('mymodule.settings');
- * $secondary_config = config('mymodule.second');
- * $tertiary_config = config('mymodule.third');
+ * $primary_config = config('my_module.settings');
+ * $secondary_config = config('my_module.second');
+ * $tertiary_config = config('my_module.third');
  * $form = array(
- *   '#config' => 'mymodule.settings',
+ *   '#config' => 'my_module.settings',
  *   'first_setting' => array(
  *     '#type' => 'textfield',
  *     '#title' => t('First Setting'),
@@ -4512,7 +4512,7 @@ function system_file_download($uri) {
  *   'bonus_fieldset' => array(
  *     '#type' => 'fieldset',
  *     '#title' => t('Secondary Settings'),
- *     '#config' => 'mymodule.second',
+ *     '#config' => 'my_module.second',
  *
  *     'bonus_one' => array( ... ),
  *     'bonus_two' => array( ... ),
@@ -4520,22 +4520,23 @@ function system_file_download($uri) {
  *     'bonus_three' => array(
  *       '#type' => 'textfield',
  *       '#default_value' => $tertiary_config->get('bonus_three'),
- *       '#config' => 'mymodule.third',
+ *       '#config' => 'my_module.third',
  *     ),
  *   ),
  * );
  * @endcode
  *
- * The top-level '#config' is "mymodule.settings". The values of 'first_setting'
- * and 'second_setting' will both be saved to "mymodule.settings".
+ * The top-level '#config' is "my_module.settings". The values of
+ * 'first_setting' and 'second_setting' will both be saved to
+ * "my_module.settings".
  *
- * The 'bonus_fieldset' has its own '#config' setting, "mymodule.second", which
+ * The 'bonus_fieldset' has its own '#config' setting, "my_module.second", which
  * overrides the top-level '#config' setting, so 'bonus_one' and 'bonus_two'
- * will be saved to "mymodule.second".
+ * will be saved to "my_module.second".
  *
- * The 'bonus_three' has its own '#config' setting, "mymodule.third", which
+ * The 'bonus_three' has its own '#config' setting, "my_module.third", which
  * overrides the one from the fieldset. The value of 'bonus_three' will be
- * saved to the "mymodule.third".
+ * saved to the "my_module.third".
  *
  * Modules that implement hook_form_alter() can use the '#config' settings to
  * save their data to their own settings file by setting the '#config' parameter
diff --git a/core/modules/system/theme.api.php b/core/modules/system/theme.api.php
index 38464ba929b..29b303daa2b 100644
--- a/core/modules/system/theme.api.php
+++ b/core/modules/system/theme.api.php
@@ -170,7 +170,7 @@ function hook_preprocess_HOOK(&$variables) {
  */
 function hook_themes_enabled($theme_list) {
   foreach ($theme_list as $theme) {
-    mymodule_prepare_theme($theme);
+    my_module_prepare_theme($theme);
   }
 }
 
diff --git a/core/modules/taxonomy/taxonomy.api.php b/core/modules/taxonomy/taxonomy.api.php
index 6968809ae1e..e86d97f5730 100644
--- a/core/modules/taxonomy/taxonomy.api.php
+++ b/core/modules/taxonomy/taxonomy.api.php
@@ -239,7 +239,7 @@ function hook_taxonomy_term_view($term, $view_mode, $langcode) {
   $term->content['my_additional_field'] = array(
     '#markup' => $additional_field,
     '#weight' => 10,
-    '#theme' => 'mymodule_my_additional_field',
+    '#theme' => 'my_module_my_additional_field',
   );
 }
 
diff --git a/core/modules/telemetry/telemetry.api.php b/core/modules/telemetry/telemetry.api.php
index 81af8e6fd47..072608c221c 100644
--- a/core/modules/telemetry/telemetry.api.php
+++ b/core/modules/telemetry/telemetry.api.php
@@ -24,16 +24,16 @@
  *     the module name, or if the project contains multiple modules.
  */
 function hook_telemetry_info() {
-  // If this were in mymodule.module, "project" would assume to be "mymodule".
-  $info['mymodule_setting_1'] = array(
+  // If this were in my_module.module, "project" would assume to be "my_module".
+  $info['my_module_setting_1'] = array(
     'label' => t('My module setting 1'),
     'description' => t('Some information about what setting 1 is.'),
   );
   // If this were in submodule.module, specify the project name explicitly.
-  $info['mymodule_submodule_setting_2'] = array(
+  $info['my_module_submodule_setting_2'] = array(
     'label' => t('Submodule setting 2'),
     'description' => t('A description describing this setting of a sub-module.'),
-    'project' => 'mymodule',
+    'project' => 'my_module',
   );
   return $info;
 }
@@ -53,7 +53,7 @@ function hook_telemetry_info_alter(array &$info) {
 
   // Prevent one particular module from reporting anything.
   foreach ($info as $info_key => $info_data) {
-    if ($info_data['module'] === 'mymodule') {
+    if ($info_data['module'] === 'my_module') {
       unset($info[$info_key]);
     }
   }
@@ -82,8 +82,8 @@ function hook_telemetry_data($telemetry_key) {
   switch ($telemetry_key) {
     case 'php_version':
       return PHP_MAJOR_VERSION . '.' . PHP_MINOR_VERSION . '.' . PHP_RELEASE_VERSION;
-    case 'mymodule_setting_1':
-      return config_get('mymodule.settings', 'setting_1');
+    case 'my_module_setting_1':
+      return config_get('my_module.settings', 'setting_1');
   }
 }
 
@@ -101,8 +101,8 @@ function hook_telemetry_data($telemetry_key) {
  * @param array $telemetry_data
  */
 function hook_telemetry_data_alter(array $telemetry_data) {
-  if (isset($telemetry_data['mymodule_setting_1'])) {
-    $telemetry_data['mymodule_setting_1'] = 'some_different_value';
+  if (isset($telemetry_data['my_module_setting_1'])) {
+    $telemetry_data['my_module_setting_1'] = 'some_different_value';
   }
 }
 
diff --git a/core/modules/user/user.api.php b/core/modules/user/user.api.php
index 4e2005c653f..13370078736 100644
--- a/core/modules/user/user.api.php
+++ b/core/modules/user/user.api.php
@@ -163,7 +163,7 @@ function hook_user_cancel_methods_alter(&$methods) {
   unset($methods['user_cancel_reassign']);
 
   // Add a custom zero-out method.
-  $methods['mymodule_zero_out'] = array(
+  $methods['my_module_zero_out'] = array(
     'title' => t('Delete the account and remove all content.'),
     'description' => t('All your content will be replaced by empty strings.'),
     // access should be used for administrative methods only.
@@ -210,10 +210,10 @@ function hook_user_format_name_alter(&$name, $account) {
  * @see hook_user_update()
  */
 function hook_user_presave($account) {
-  // Make sure that our form value 'mymodule_foo' is stored as
-  // 'mymodule_bar' in the 'data' (serialized) column.
-  if (isset($account->mymodule_foo)) {
-    $account->data['mymodule_bar'] = $account->mymodule_foo;
+  // Make sure that our form value 'my_module_foo' is stored as
+  // 'my_module_bar' in the 'data' (serialized) column.
+  if (isset($account->my_module_foo)) {
+    $account->data['my_module_bar'] = $account->my_module_foo;
   }
 }
 
diff --git a/core/modules/views/views.api.php b/core/modules/views/views.api.php
index a40f84cd1ba..69f8fca63a8 100644
--- a/core/modules/views/views.api.php
+++ b/core/modules/views/views.api.php
@@ -964,7 +964,7 @@ function hook_views_ajax_data_alter(&$commands, $view) {
  * @see views_invalidate_cache()
  */
 function hook_views_invalidate_cache() {
-  cache('mymodule')->deletePrefix('views:');
+  cache('my_module')->deletePrefix('views:');
 }
 
 /**