diff --git a/core/modules/aggregator/aggregator.module b/core/modules/aggregator/aggregator.module
index caac2790d7c..0626f726e3c 100644
--- a/core/modules/aggregator/aggregator.module
+++ b/core/modules/aggregator/aggregator.module
@@ -789,7 +789,7 @@ function _aggregator_items($count) {
 }
 
 /**
- * Implements hook_preprocess_block().
+ * Implements hook_preprocess_HOOK() for block.tpl.php.
  */
 function aggregator_preprocess_block(&$variables) {
   if ($variables['block']->module == 'aggregator') {
diff --git a/core/modules/book/book.module b/core/modules/book/book.module
index 44de175b656..c102849c699 100644
--- a/core/modules/book/book.module
+++ b/core/modules/book/book.module
@@ -1065,7 +1065,7 @@ function _book_link_defaults($nid) {
 }
 
  /**
- * Implements hook_preprocess_block().
+ * Implements hook_preprocess_HOOK() for block.tpl.php.
  */
 function book_preprocess_block(&$variables) {
   if ($variables['block']-> module == 'book') {
diff --git a/core/modules/comment/comment.api.php b/core/modules/comment/comment.api.php
index c6555578e0d..537458634bb 100644
--- a/core/modules/comment/comment.api.php
+++ b/core/modules/comment/comment.api.php
@@ -85,8 +85,9 @@ function hook_comment_view(Drupal\comment\Comment $comment, $view_mode, $langcod
  *
  * If the module wishes to act on the rendered HTML of the comment rather than
  * the structured content array, it may use this hook to add a #post_render
- * callback. Alternatively, it could also implement hook_preprocess_comment().
- * See drupal_render() and theme() documentation respectively for details.
+ * callback. Alternatively, it could also implement hook_preprocess_HOOK() for
+ * comment.tpl.php. See drupal_render() and theme() documentation respectively
+ * for details.
  *
  * @param $build
  *   A renderable array representing the comment.
diff --git a/core/modules/comment/comment.module b/core/modules/comment/comment.module
index e70b136dad7..179c46a09cb 100644
--- a/core/modules/comment/comment.module
+++ b/core/modules/comment/comment.module
@@ -2099,7 +2099,7 @@ function comment_form_submit($form, &$form_state) {
 }
 
 /**
- * Implements hook_preprocess_block().
+ * Implements hook_preprocess_HOOK() for block.tpl.php.
  */
 function comment_preprocess_block(&$variables) {
   if ($variables['block']->module == 'comment') {
diff --git a/core/modules/entity/entity.api.php b/core/modules/entity/entity.api.php
index 0f8f7b8605c..f49b76133b8 100644
--- a/core/modules/entity/entity.api.php
+++ b/core/modules/entity/entity.api.php
@@ -400,7 +400,8 @@ function hook_entity_view($entity, $type, $view_mode, $langcode) {
  *
  * If a module wishes to act on the rendered HTML of the entity rather than the
  * structured content array, it may use this hook to add a #post_render
- * callback. Alternatively, it could also implement hook_preprocess_ENTITY().
+ * callback. Alternatively, it could also implement hook_preprocess_HOOK() for
+ * the particular entity type template, if there is one (e.g., node.tpl.php).
  * See drupal_render() and theme() for details.
  *
  * @param $build
diff --git a/core/modules/forum/forum.module b/core/modules/forum/forum.module
index 2d7313f9d53..1b0ab983232 100644
--- a/core/modules/forum/forum.module
+++ b/core/modules/forum/forum.module
@@ -982,7 +982,7 @@ function forum_get_topics($tid, $sortby, $forum_per_page) {
 }
 
 /**
- * Implements hook_preprocess_block().
+ * Implements hook_preprocess_HOOK() for block.tpl.php.
  */
 function forum_preprocess_block(&$variables) {
   if ($variables['block']->module == 'forum') {
diff --git a/core/modules/help/help.module b/core/modules/help/help.module
index e4899a05b02..dbc836c9da5 100644
--- a/core/modules/help/help.module
+++ b/core/modules/help/help.module
@@ -66,7 +66,7 @@ function help_help($path, $arg) {
 }
 
 /**
- * Implements hook_preprocess_block().
+ * Implements hook_preprocess_HOOK() for block.tpl.php.
  */
 function help_preprocess_block(&$variables) {
   if ($variables['block']->module == 'system' && $variables['block']->delta == 'help') {
diff --git a/core/modules/language/language.module b/core/modules/language/language.module
index c7d6f1822d2..7acc78364b8 100644
--- a/core/modules/language/language.module
+++ b/core/modules/language/language.module
@@ -477,7 +477,7 @@ function language_block_view($type) {
 }
 
 /**
- * Implements hook_preprocess_block().
+ * Implements hook_preprocess_HOOK() for block.tpl.php.
  */
 function language_preprocess_block(&$variables) {
   if ($variables['block']->module == 'language') {
diff --git a/core/modules/locale/locale.module b/core/modules/locale/locale.module
index 357166035b8..35f8032b5d1 100644
--- a/core/modules/locale/locale.module
+++ b/core/modules/locale/locale.module
@@ -781,7 +781,7 @@ function locale_form_system_file_system_settings_alter(&$form, $form_state) {
 }
 
 /**
- * Implements MODULE_preprocess_HOOK().
+ * Implements hook_preprocess_HOOK() for node.tpl.php.
  */
 function locale_preprocess_node(&$variables) {
   if ($variables['langcode'] != LANGUAGE_NOT_SPECIFIED) {
diff --git a/core/modules/menu/menu.module b/core/modules/menu/menu.module
index 81094d07c53..466cd88cbc5 100644
--- a/core/modules/menu/menu.module
+++ b/core/modules/menu/menu.module
@@ -796,7 +796,7 @@ function menu_get_menus($all = TRUE) {
 }
 
 /**
- * Implements hook_preprocess_block().
+ * Implements hook_preprocess_HOOK() for block.tpl.php.
  */
 function menu_preprocess_block(&$variables) {
   if ($variables['block']->module == 'menu') {
diff --git a/core/modules/node/node.api.php b/core/modules/node/node.api.php
index 2511ce5bdd8..783bf6ec5c1 100644
--- a/core/modules/node/node.api.php
+++ b/core/modules/node/node.api.php
@@ -834,8 +834,9 @@ function hook_node_view(Drupal\node\Node $node, $view_mode, $langcode) {
  *
  * If the module wishes to act on the rendered HTML of the node rather than the
  * structured content array, it may use this hook to add a #post_render
- * callback.  Alternatively, it could also implement hook_preprocess_node(). See
- * drupal_render() and theme() documentation respectively for details.
+ * callback.  Alternatively, it could also implement hook_preprocess_HOOK() for
+ * node.tpl.php. See drupal_render() and theme() documentation respectively
+ * for details.
  *
  * @param $build
  *   A renderable array representing the node content.
diff --git a/core/modules/node/node.module b/core/modules/node/node.module
index 9e21bfaa0e7..f9c213d2a24 100644
--- a/core/modules/node/node.module
+++ b/core/modules/node/node.module
@@ -1302,7 +1302,7 @@ function node_is_page(Node $node) {
 }
 
  /**
- * Implements hook_preprocess_block().
+ * Implements hook_preprocess_HOOK() for block.tpl.php.
  */
 function node_preprocess_block(&$variables) {
   if ($variables['block']->module == 'node') {
diff --git a/core/modules/overlay/overlay.module b/core/modules/overlay/overlay.module
index 271f15dd5a9..02c0883d21a 100644
--- a/core/modules/overlay/overlay.module
+++ b/core/modules/overlay/overlay.module
@@ -445,7 +445,7 @@ function overlay_system_info_alter(&$info, $file, $type) {
 }
 
 /**
- * Implements hook_preprocess_html().
+ * Implements hook_preprocess_HOOK() for html.tpl.php.
  *
  * If the current page request is inside the overlay, add appropriate classes
  * to the <body> element, and simplify the page title.
@@ -460,12 +460,10 @@ function overlay_preprocess_html(&$variables) {
 }
 
 /**
- * Implements hook_preprocess_maintenance_page().
+ * Implements hook_preprocess_HOOK() for maintenance-page.tpl.php.
  *
  * If the current page request is inside the overlay, add appropriate classes
  * to the <body> element, and simplify the page title.
- *
- * @see overlay_preprocess_maintenance_page()
  */
 function overlay_preprocess_maintenance_page(&$variables) {
   overlay_preprocess_html($variables);
@@ -495,7 +493,7 @@ function template_process_overlay(&$variables) {
 }
 
 /**
- * Implements hook_preprocess_page().
+ * Implements hook_preprocess_HOOK() for page.tpl.php.
  *
  * Hide tabs inside the overlay.
  *
diff --git a/core/modules/poll/poll.module b/core/modules/poll/poll.module
index beba2ed6d32..b62568c1a5a 100644
--- a/core/modules/poll/poll.module
+++ b/core/modules/poll/poll.module
@@ -775,7 +775,7 @@ function poll_vote($form, &$form_state) {
 }
 
 /**
- * Implements hook_preprocess_block().
+ * Implements hook_preprocess_HOOK() for block.tpl.php.
  */
 function poll_preprocess_block(&$variables) {
   if ($variables['block']->module == 'poll') {
diff --git a/core/modules/rdf/rdf.module b/core/modules/rdf/rdf.module
index 8f9c02563ee..43ee4ed69e3 100644
--- a/core/modules/rdf/rdf.module
+++ b/core/modules/rdf/rdf.module
@@ -461,7 +461,7 @@ function rdf_process(&$variables, $hook) {
 }
 
 /**
- * Implements MODULE_preprocess_HOOK()
+ * Implements hook_preprocess_HOOK() for html.tpl.php.
  */
 function rdf_preprocess_html(&$variables) {
   // Adds RDF namespace prefix bindings in the form of an RDFa 1.1 prefix
@@ -473,7 +473,7 @@ function rdf_preprocess_html(&$variables) {
 }
 
 /**
- * Implements MODULE_preprocess_HOOK().
+ * Implements hook_preprocess_HOOK() for node.tpl.php.
  */
 function rdf_preprocess_node(&$variables) {
   // Adds RDFa markup to the node container. The about attribute specifies the
@@ -556,7 +556,7 @@ function rdf_preprocess_node(&$variables) {
 }
 
 /**
- * Implements MODULE_preprocess_HOOK().
+ * Implements hook_preprocess_HOOK() for field.tpl.php.
  */
 function rdf_preprocess_field(&$variables) {
   $element = $variables['element'];
@@ -584,7 +584,7 @@ function rdf_preprocess_field(&$variables) {
 }
 
 /**
- * Implements MODULE_preprocess_HOOK().
+ * Implements hook_preprocess_HOOK() for user-profile.tpl.php.
  */
 function rdf_preprocess_user_profile(&$variables) {
   $account = $variables['elements']['#account'];
@@ -621,7 +621,7 @@ function rdf_preprocess_user_profile(&$variables) {
 }
 
 /**
- * Implements MODULE_preprocess_HOOK().
+ * Implements hook_preprocess_HOOK() for theme_username().
  */
 function rdf_preprocess_username(&$variables) {
   // Because lang is set on the HTML element that wraps the page, the
@@ -676,7 +676,7 @@ function rdf_preprocess_username(&$variables) {
 }
 
 /**
- * Implements MODULE_preprocess_HOOK().
+ * Implements hook_preprocess_HOOK() for comment.tpl.php.
  */
 function rdf_preprocess_comment(&$variables) {
   $comment = $variables['comment'];
@@ -734,7 +734,7 @@ function rdf_preprocess_comment(&$variables) {
 }
 
 /**
- * Implements MODULE_preprocess_HOOK().
+ * Implements hook_preprocess_HOOK() for taxonomy-term.tpl.php.
  */
 function rdf_preprocess_taxonomy_term(&$variables) {
   // Adds the RDF type of the term and the term name in a <meta> tag.
@@ -778,7 +778,7 @@ function rdf_field_attach_view_alter(&$output, $context) {
 }
 
 /**
- * Implements MODULE_preprocess_HOOK().
+ * Implements hook_preprocess_HOOK() for theme_image().
  */
 function rdf_preprocess_image(&$variables) {
   // Adds the RDF type for image.  We cannot use the usual entity-based mapping
@@ -830,11 +830,11 @@ function rdf_preprocess_image(&$variables) {
  *     wrapped by a <span> tag. Modules implementing preprocess functions that
  *     set 'rdf_template_variable_attributes_array' for a particular template
  *     variable that might contain block level HTML must also implement
- *     hook_preprocess_rdf_template_variable_wrapper() and set 'inline' to FALSE
- *     for that context. Themes that render normally inline content with block
- *     level HTML must similarly implement
- *     hook_preprocess_rdf_template_variable_wrapper() and set 'inline'
- *     accordingly.
+ *     hook_preprocess_HOOK() for theme_rdf_template_variable_wrapper() and set
+ *     'inline' to FALSE for that context. Themes that render normally inline
+ *     content with block level HTML must similarly implement
+ *     hook_preprocess_HOOK() for theme_rdf_template_variable_wrapper() and set
+ *     'inline' accordingly.
  *
  * @see rdf_process()
  * @ingroup themeable
diff --git a/core/modules/search/search.module b/core/modules/search/search.module
index 4e761505557..1ad7a850f89 100644
--- a/core/modules/search/search.module
+++ b/core/modules/search/search.module
@@ -156,7 +156,7 @@ function search_block_view($delta = '') {
 }
 
 /**
- * Implements hook_preprocess_block().
+ * Implements hook_preprocess_HOOK() for block.tpl.php.
  */
 function search_preprocess_block(&$variables) {
   if ($variables['block']->module == 'search' && $variables['block']->delta == 'form') {
diff --git a/core/modules/shortcut/shortcut.module b/core/modules/shortcut/shortcut.module
index 73b63850eae..be29dce9199 100644
--- a/core/modules/shortcut/shortcut.module
+++ b/core/modules/shortcut/shortcut.module
@@ -640,7 +640,7 @@ function shortcut_renderable_links($shortcut_set = NULL) {
 }
 
 /**
- * Implements hook_preprocess_block().
+ * Implements hook_preprocess_HOOK() for block.tpl.php.
  */
 function shortcut_preprocess_block(&$variables) {
   if ($variables['block']->module == 'shortcut') {
@@ -649,7 +649,7 @@ function shortcut_preprocess_block(&$variables) {
 }
 
 /**
- * Implements hook_preprocess_page().
+ * Implements hook_preprocess_HOOK() for page.tpl.php.
  */
 function shortcut_preprocess_page(&$variables) {
   // Only display the shortcut link if the user has the ability to edit
diff --git a/core/modules/statistics/statistics.module b/core/modules/statistics/statistics.module
index 654621dbc45..ef1bceb63ee 100644
--- a/core/modules/statistics/statistics.module
+++ b/core/modules/statistics/statistics.module
@@ -449,7 +449,7 @@ function statistics_update_index() {
 }
 
 /**
- * Implements hook_preprocess_block().
+ * Implements hook_preprocess_HOOK() for block.tpl.php.
  */
 function statistics_preprocess_block(&$variables) {
   if ($variables['block']->module == 'statistics') {
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index 8af6cc3938f..aa9dc8f25a2 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -2118,7 +2118,7 @@ function system_block_view($delta = '') {
 }
 
 /**
- * Implements hook_preprocess_block().
+ * Implements hook_preprocess_HOOK() for block.tpl.php.
  */
 function system_preprocess_block(&$variables) {
   if ($variables['block']->module == 'system') {
diff --git a/core/modules/system/tests/modules/theme_test/theme_test.module b/core/modules/system/tests/modules/theme_test/theme_test.module
index 265cf80739f..4ed90d2c749 100644
--- a/core/modules/system/tests/modules/theme_test/theme_test.module
+++ b/core/modules/system/tests/modules/theme_test/theme_test.module
@@ -139,7 +139,7 @@ function _theme_test_suggestion() {
 }
 
 /**
- * Implements hook_preprocess_html().
+ * Implements hook_preprocess_HOOK() for html.tpl.php.
  */
 function theme_test_preprocess_html(&$variables) {
   $variables['html_attributes_array']['theme_test_html_attribute'] = 'theme test html attribute value';
diff --git a/core/modules/system/tests/theme.test b/core/modules/system/tests/theme.test
index 2a1959c7789..025ae8d7d88 100644
--- a/core/modules/system/tests/theme.test
+++ b/core/modules/system/tests/theme.test
@@ -591,9 +591,9 @@ class ThemeHtmlTplPhpAttributesTestCase extends DrupalWebTestCase {
   function testThemeHtmlTplPhpAttributes() {
     $this->drupalGet('');
     $attributes = $this->xpath('/html[@theme_test_html_attribute="theme test html attribute value"]');
-    $this->assertTrue(count($attributes) == 1, t('Attribute set in the html element via hook_preprocess_html() found.'));
+    $this->assertTrue(count($attributes) == 1, 'Attribute set in the html element via hook_preprocess_HOOK() for html.tpl.php found.');
     $attributes = $this->xpath('/html/body[@theme_test_body_attribute="theme test body attribute value"]');
-    $this->assertTrue(count($attributes) == 1, t('Attribute set in the body element via hook_preprocess_html() found.'));
+    $this->assertTrue(count($attributes) == 1, 'Attribute set in the body element via hook_preprocess_HOOK() for html.tpl.php found.');
   }
 }
 
diff --git a/core/modules/taxonomy/taxonomy.api.php b/core/modules/taxonomy/taxonomy.api.php
index 84fdfc76186..88a0ff55006 100644
--- a/core/modules/taxonomy/taxonomy.api.php
+++ b/core/modules/taxonomy/taxonomy.api.php
@@ -232,8 +232,8 @@ function hook_taxonomy_term_delete(TaxonomyTerm $term) {
  * If the module wishes to act on the rendered HTML of the term rather than the
  * structured content array, it may use this hook to add a #post_render
  * callback. Alternatively, it could also implement
- * hook_preprocess_taxonomy_term(). See drupal_render() and theme()
- * documentation respectively for details.
+ * hook_preprocess_HOOK() for taxonomy-term.tpl.php. See drupal_render() and
+ * theme() documentation respectively for details.
  *
  * @param $build
  *   A renderable array representing the taxonomy term content.
diff --git a/core/modules/toolbar/toolbar.module b/core/modules/toolbar/toolbar.module
index e2bff730637..904a2f8a3c7 100644
--- a/core/modules/toolbar/toolbar.module
+++ b/core/modules/toolbar/toolbar.module
@@ -140,7 +140,7 @@ function toolbar_pre_render($toolbar) {
 }
 
 /**
- * Implements hook_preprocess_html().
+ * Implements hook_preprocess_HOOK() for html.tpl.php.
  *
  * Add some page classes, so global page theming can adjust to the toolbar.
  */
@@ -154,7 +154,7 @@ function toolbar_preprocess_html(&$vars) {
 }
 
 /**
- * Implements hook_preprocess_toolbar().
+ * Implements hook_preprocess_HOOK() for toolbar.tpl.php.
  *
  * Adding the 'overlay-displace-top' class to the toolbar pushes the overlay
  * down, so it appears below the toolbar.
diff --git a/core/modules/user/user.api.php b/core/modules/user/user.api.php
index 1b8a2532631..8c7286e16e2 100644
--- a/core/modules/user/user.api.php
+++ b/core/modules/user/user.api.php
@@ -353,8 +353,9 @@ function hook_user_view($account, $view_mode, $langcode) {
  *
  * If the module wishes to act on the rendered HTML of the user rather than the
  * structured content array, it may use this hook to add a #post_render callback.
- * Alternatively, it could also implement hook_preprocess_user_profile(). See
- * drupal_render() and theme() documentation respectively for details.
+ * Alternatively, it could also implement hook_preprocess_HOOK() for
+ * user-profile.tpl.php. See drupal_render() and theme() documentation
+ * respectively for details.
  *
  * @param $build
  *   A renderable array representing the user.
diff --git a/core/modules/user/user.module b/core/modules/user/user.module
index 4219728ab8b..0589862ca83 100644
--- a/core/modules/user/user.module
+++ b/core/modules/user/user.module
@@ -1172,7 +1172,7 @@ function user_block_view($delta = '') {
 }
 
 /**
- * Implements hook_preprocess_block().
+ * Implements hook_preprocess_HOOK() for block.tpl.php.
  */
 function user_preprocess_block(&$variables) {
   if ($variables['block']->module == 'user') {