diff --git a/core/includes/menu.inc b/core/includes/menu.inc
index 2e2c50d..e51dac5 100644
--- a/core/includes/menu.inc
+++ b/core/includes/menu.inc
@@ -509,108 +509,6 @@ function menu_get_item($path = NULL, $router_item = NULL) {
 }
 
 /**
- * Loads objects into the map as defined in the $item['load_functions'].
- *
- * @param $item
- *   A menu router or menu link item
- * @param $map
- *   An array of path arguments; for example, array('node', '5').
- *
- * @return
- *   Returns TRUE for success, FALSE if an object cannot be loaded.
- *   Names of object loading functions are placed in $item['load_functions'].
- *   Loaded objects are placed in $map[]; keys are the same as keys in the
- *   $item['load_functions'] array.
- *   $item['access'] is set to FALSE if an object cannot be loaded.
- */
-function _menu_load_objects(&$item, &$map) {
-  if ($load_functions = $item['load_functions']) {
-    // If someone calls this function twice, then unserialize will fail.
-    if (!is_array($load_functions)) {
-      $load_functions = unserialize($load_functions);
-    }
-    $path_map = $map;
-    foreach ($load_functions as $index => $function) {
-      if ($function) {
-        $value = isset($path_map[$index]) ? $path_map[$index] : '';
-        if (is_array($function)) {
-          // Set up arguments for the load function. These were pulled from
-          // 'load arguments' in the hook_menu() entry, but they need
-          // some processing. In this case the $function is the key to the
-          // load_function array, and the value is the list of arguments.
-          list($function, $args) = each($function);
-          $load_functions[$index] = $function;
-
-          // Some arguments are placeholders for dynamic items to process.
-          foreach ($args as $i => $arg) {
-            if ($arg === '%index') {
-              // Pass on argument index to the load function, so multiple
-              // occurrences of the same placeholder can be identified.
-              $args[$i] = $index;
-            }
-            if ($arg === '%map') {
-              // Pass on menu map by reference. The accepting function must
-              // also declare this as a reference if it wants to modify
-              // the map.
-              $args[$i] = &$map;
-            }
-            if (is_int($arg)) {
-              $args[$i] = isset($path_map[$arg]) ? $path_map[$arg] : '';
-            }
-          }
-          array_unshift($args, $value);
-          $return = call_user_func_array($function, $args);
-        }
-        else {
-          $return = $function($value);
-        }
-        // If callback returned an error or there is no callback, trigger 404.
-        if (empty($return)) {
-          $item['access'] = FALSE;
-          $map = FALSE;
-          return FALSE;
-        }
-        $map[$index] = $return;
-      }
-    }
-    $item['load_functions'] = $load_functions;
-  }
-  return TRUE;
-}
-
-/**
- * Checks access to a menu item using the access callback.
- *
- * @param $item
- *   A menu router or menu link item
- * @param $map
- *   An array of path arguments; for example, array('node', '5').
- *
- * @return
- *   $item['access'] becomes TRUE if the item is accessible, FALSE otherwise.
- */
-function _menu_check_access(&$item, $map) {
-  // Determine access callback, which will decide whether or not the current
-  // user has access to this path.
-  $callback = empty($item['access_callback']) ? 0 : trim($item['access_callback']);
-  // Check for a TRUE or FALSE value.
-  if (is_numeric($callback)) {
-    $item['access'] = (bool) $callback;
-  }
-  else {
-    $arguments = menu_unserialize($item['access_arguments'], $map);
-    // As call_user_func_array is quite slow and user_access is a very common
-    // callback, it is worth making a special case for it.
-    if ($callback == 'user_access') {
-      $item['access'] = (count($arguments) == 1) ? user_access($arguments[0]) : user_access($arguments[0], $arguments[1]);
-    }
-    else {
-      $item['access'] = call_user_func_array($callback, $arguments);
-    }
-  }
-}
-
-/**
  * Localizes the router item title using t() or another callback.
  *
  * Translate the title and description to allow storage of English title
@@ -746,19 +644,9 @@ function _menu_item_localize(&$item, $map, $link_translate = FALSE) {
  *   a non-existent node) then this function returns FALSE.
  */
 function _menu_translate(&$router_item, $map, $to_arg = FALSE) {
-  if ($to_arg && !empty($router_item['to_arg_functions'])) {
-    // Fill in missing path elements, such as the current uid.
-    _menu_link_map_translate($map, $router_item['to_arg_functions']);
-  }
   // The $path_map saves the pieces of the path as strings, while elements in
   // $map may be replaced with loaded objects.
   $path_map = $map;
-  if (!empty($router_item['load_functions']) && !_menu_load_objects($router_item, $map)) {
-    // An error occurred loading an object.
-    $router_item['access'] = FALSE;
-    return FALSE;
-  }
-
   // Generate the link path for the page request or local tasks.
   $link_map = explode('/', $router_item['path']);
   if (isset($router_item['tab_root'])) {
@@ -791,9 +679,12 @@ function _menu_translate(&$router_item, $map, $to_arg = FALSE) {
     $route = $route_provider->getRouteByName($router_item['route_name']);
     $router_item['access'] = menu_item_route_access($route, $router_item['href'], $map);
   }
+  // @todo Remove once all local tasks are converted.
+  elseif (isset($router_item['type']) && $router_item['type'] == MENU_DEFAULT_LOCAL_TASK) {
+    $router_item['access'] = TRUE;
+  }
   else {
-    // @todo: Remove once all routes are converted.
-    _menu_check_access($router_item, $map);
+    $router_item['access'] = FALSE;
   }
 
   // For performance, don't localize an item the user can't access.
@@ -805,54 +696,6 @@ function _menu_translate(&$router_item, $map, $to_arg = FALSE) {
 }
 
 /**
- * Translates the path elements in the map using any to_arg helper function.
- *
- * @param $map
- *   An array of path arguments; for example, array('node', '5').
- * @param $to_arg_functions
- *   An array of helper functions; for example, array(2 => 'menu_tail_to_arg').
- *
- * @see hook_menu()
- */
-function _menu_link_map_translate(&$map, $to_arg_functions) {
-  $to_arg_functions = unserialize($to_arg_functions);
-  foreach ($to_arg_functions as $index => $function) {
-    // Translate place-holders into real values.
-    $arg = $function(!empty($map[$index]) ? $map[$index] : '', $map, $index);
-    if (!empty($map[$index]) || isset($arg)) {
-      $map[$index] = $arg;
-    }
-    else {
-      unset($map[$index]);
-    }
-  }
-}
-
-/**
- * Returns a string containing the path relative to the current index.
- */
-function menu_tail_to_arg($arg, $map, $index) {
-  return implode('/', array_slice($map, $index));
-}
-
-/**
- * Loads the path as one string relative to the current index.
- *
- * To use this load function, you must specify the load arguments
- * in the router item as:
- * @code
- * $item['load arguments'] = array('%map', '%index');
- * @endcode
- *
- * @see search_menu().
- */
-function menu_tail_load($arg, &$map, $index) {
-  $arg = implode('/', array_slice($map, $index));
-  $map = array_slice($map, 0, $index);
-  return $arg;
-}
-
-/**
  * Provides menu link access control, translation, and argument handling.
  *
  * This function is similar to _menu_translate(), but it also does
@@ -890,18 +733,14 @@ function _menu_link_translate(&$item, $translate = FALSE) {
     // if it contains dynamic placeholders (%).
     $map = explode('/', $item['link_path']);
     if (strpos($item['link_path'], '%') !== FALSE) {
-      // Invoke registered to_arg callbacks.
-      if (!empty($item['to_arg_functions'])) {
-        _menu_link_map_translate($map, $item['to_arg_functions']);
-      }
-      // Or try to derive the path argument map from the current router item,
+      // Try to derive the path argument map from the current router item,
       // if this $item's path is within the router item's path. This means
       // that if we are on the current path 'foo/%/bar/%/baz', then
       // menu_get_item() will have translated the menu router item for the
       // current path, and we can take over the argument map for a link like
       // 'foo/%/bar'. This inheritance is only valid for breadcrumb links.
       // @see _menu_tree_check_access()
-      elseif ($translate && ($current_router_item = menu_get_item())) {
+      if ($translate && ($current_router_item = menu_get_item())) {
         // If $translate is TRUE, then this link is in the active trail.
         // Only translate paths within the current path.
         if (strpos($current_router_item['path'], $item['link_path']) === 0) {
@@ -928,15 +767,12 @@ function _menu_link_translate(&$item, $translate = FALSE) {
       if ($route = $item->getRoute()) {
         $item['access'] = menu_item_route_access($route, $item['href'], $map);
       }
-      elseif (!empty($item['load_functions']) && !_menu_load_objects($item, $map)) {
-        // An error occurred loading an object.
-        $item['access'] = FALSE;
-        return FALSE;
+      // @todo Remove once all local tasks are converted.
+      elseif (isset($item['type']) && $item['type'] == MENU_DEFAULT_LOCAL_TASK) {
+        $item['access'] = TRUE;
       }
-      // Apply the access check defined in hook_menu() if there is not route
-      // defined.
       else {
-        _menu_check_access($item, $map);
+        $item['access'] = FALSE;
       }
     }
     // For performance, don't localize a link the user can't access.
@@ -1036,10 +872,6 @@ function menu_get_object($type = 'node', $position = 1, $path = NULL) {
     return;
   }
 
-  if (isset($router_item['load_functions'][$position]) && $router_item['load_functions'][$position] == $type . '_load') {
-    return $router_item['map'][$position];
-  }
-
   // If the path is route-based, use the route path instead of the menu item.
   // The most common use of this function is for the node page, which has a
   // route path of '/node/{node}'. By splitting that path into parts, we check
@@ -2578,21 +2410,11 @@ function menu_router_build($save = FALSE) {
   foreach ($callbacks as $path => $router_item) {
     // If the menu item is a default local task and incorrectly references a
     // route, remove it.
-    // @todo This may be removed later depending on the outcome of
-    // http://drupal.org/node/1889790
+    // @todo Remove once all local tasks are converted.
     if (isset($router_item['type']) && $router_item['type'] == MENU_DEFAULT_LOCAL_TASK) {
       unset($callbacks[$path]['route_name']);
-    }
-    // If the menu item references a route, normalize the route information
-    // into the old structure. Note that routes are keyed by name, not path,
-    // so the path of the route takes precedence.
-    if (isset($router_item['route_name'])) {
-      $router_item['page callback'] = 'USES_ROUTE';
-      $router_item['access callback'] = TRUE;
-      $new_path = _menu_router_translate_route($router_item['route_name']);
-
-      unset($callbacks[$path]);
-      $callbacks[$new_path] = $router_item;
+      $callbacks[$path]['page callback'] = 'USES_ROUTE';
+      $callbacks[$path]['access callback'] = TRUE;
     }
   }
   list($menu, $masks) = _menu_router_build($callbacks, $save);
@@ -2602,23 +2424,6 @@ function menu_router_build($save = FALSE) {
 }
 
 /**
- * Translates a route name to its router item path.
- *
- * @param string $route_name
- *   The route name to translate.
- *
- * @return string
- *   The translated path pattern from the route.
- */
-function _menu_router_translate_route($route_name) {
-  $outline = \Drupal::service('router.route_provider')
-    ->getRouteByName($route_name)
-    ->compile()
-    ->getPatternOutline();
-  return trim($outline, '/');
-}
-
-/**
  * Stores the menu router if we have it in memory.
  */
 function _menu_router_cache($new_menu = NULL) {
@@ -2895,21 +2700,6 @@ function _menu_router_build($callbacks, $save = FALSE) {
           $match = TRUE;
           $load_functions[$k] = NULL;
         }
-        else {
-          if (function_exists($matches[1] . '_to_arg')) {
-            $to_arg_functions[$k] = $matches[1] . '_to_arg';
-            $load_functions[$k] = NULL;
-            $match = TRUE;
-          }
-          if (function_exists($matches[1] . '_load')) {
-            $function = $matches[1] . '_load';
-            // Create an array of arguments that will be passed to the _load
-            // function when this menu path is checked, if 'load arguments'
-            // exists.
-            $load_functions[$k] = isset($item['load arguments']) ? array($function => $item['load arguments']) : $function;
-            $match = TRUE;
-          }
-        }
       }
       if ($match) {
         $parts[$k] = '%';
@@ -3020,21 +2810,6 @@ function _menu_router_build($callbacks, $save = FALSE) {
             }
           }
         }
-        // Same for load arguments: if a loader doesn't have any explict
-        // arguments, try to find arguments in the parent.
-        if (!isset($item['load arguments'])) {
-          foreach ($item['_load_functions'] as $k => $function) {
-            // This loader doesn't have any explict arguments...
-            if (!is_array($function)) {
-              // ... check the parent for a loader at the same position
-              // using the same function name and defining arguments...
-              if (isset($parent['_load_functions'][$k]) && is_array($parent['_load_functions'][$k]) && key($parent['_load_functions'][$k]) === $function) {
-                // ... and inherit the arguments on the child.
-                $item['_load_functions'][$k] = $parent['_load_functions'][$k];
-              }
-            }
-          }
-        }
       }
     }
     if (!isset($item['access callback']) && isset($item['access arguments'])) {
@@ -3048,7 +2823,7 @@ function _menu_router_build($callbacks, $save = FALSE) {
       $item['access callback'] = intval($item['access callback']);
     }
 
-    $item['load_functions'] = empty($item['_load_functions']) ? '' : serialize($item['_load_functions']);
+    $item['load_functions'] = '';
     $item += array(
       'access arguments' => array(),
       'access callback' => '',
diff --git a/core/modules/aggregator/aggregator.module b/core/modules/aggregator/aggregator.module
index 726f228..d46f873 100644
--- a/core/modules/aggregator/aggregator.module
+++ b/core/modules/aggregator/aggregator.module
@@ -97,11 +97,11 @@ function aggregator_menu() {
     'route_name' => 'aggregator.admin_overview',
     'weight' => 10,
   );
-  $items['admin/config/services/aggregator/remove/%aggregator_feed'] = array(
+  $items['admin/config/services/aggregator/remove/%'] = array(
     'title' => 'Remove items',
     'route_name' => 'aggregator.feed_items_delete',
   );
-  $items['admin/config/services/aggregator/update/%aggregator_feed'] = array(
+  $items['admin/config/services/aggregator/update/%'] = array(
     'title' => 'Update items',
     'route_name' => 'aggregator.feed_refresh',
   );
@@ -118,29 +118,29 @@ function aggregator_menu() {
     'title' => 'Categories',
     'route_name' => 'aggregator.categories',
   );
-  $items['aggregator/categories/%aggregator_category'] = array(
+  $items['aggregator/categories/%'] = array(
     'title callback' => '_aggregator_category_title',
     'title arguments' => array(2),
     'route_name' => 'aggregator.category_view',
   );
-  $items['aggregator/sources/%aggregator_feed'] = array(
+  $items['aggregator/sources/%'] = array(
     'title callback' => 'entity_page_label',
     'title arguments' => array(2),
     'route_name' => 'aggregator.feed_view',
   );
-  $items['admin/config/services/aggregator/edit/feed/%aggregator_feed'] = array(
+  $items['admin/config/services/aggregator/edit/feed/%'] = array(
     'title' => 'Edit feed',
     'route_name' => 'aggregator.feed_edit',
   );
-  $items['admin/config/services/aggregator/delete/feed/%aggregator_feed'] = array(
+  $items['admin/config/services/aggregator/delete/feed/%'] = array(
     'title' => 'Delete feed',
     'route_name' => 'aggregator.feed_delete',
   );
-  $items['admin/config/services/aggregator/edit/category/%aggregator_category'] = array(
+  $items['admin/config/services/aggregator/edit/category/%'] = array(
     'title' => 'Edit category',
     'route_name' => 'aggregator.category_admin_edit',
   );
-  $items['admin/config/services/aggregator/delete/category/%aggregator_category'] = array(
+  $items['admin/config/services/aggregator/delete/category/%'] = array(
     'title' => 'Delete category',
     'route_name' => 'aggregator.category_delete',
   );
diff --git a/core/modules/block/block.module b/core/modules/block/block.module
index afe5862..23d6367 100644
--- a/core/modules/block/block.module
+++ b/core/modules/block/block.module
@@ -100,11 +100,11 @@ function block_menu() {
     'description' => 'Configure what block content appears in your site\'s sidebars and other regions.',
     'route_name' => 'block.admin_display',
   );
-  $items['admin/structure/block/manage/%block'] = array(
+  $items['admin/structure/block/manage/%'] = array(
     'title' => 'Configure block',
     'route_name' => 'block.admin_edit',
   );
-  $items['admin/structure/block/add/%/%'] = array(
+  $items['admin/structure/block/add/%'] = array(
     'title' => 'Place block',
     'type' => MENU_VISIBLE_IN_BREADCRUMB,
     'route_name' => 'block.admin_add',
diff --git a/core/modules/block/custom_block/custom_block.module b/core/modules/block/custom_block/custom_block.module
index 4cf2e68..b7f9399 100644
--- a/core/modules/block/custom_block/custom_block.module
+++ b/core/modules/block/custom_block/custom_block.module
@@ -67,7 +67,7 @@ function custom_block_menu() {
     'type' => MENU_NORMAL_ITEM,
   );
 
-  $items['admin/structure/block/custom-blocks/manage/%custom_block_type'] = array(
+  $items['admin/structure/block/custom-blocks/manage/%'] = array(
     'title' => 'Edit custom block type',
     'title callback' => 'entity_page_label',
     'title arguments' => array(5),
diff --git a/core/modules/block/custom_block/tests/modules/custom_block_test/custom_block_test.module b/core/modules/block/custom_block/tests/modules/custom_block_test/custom_block_test.module
index b9e848c..b8497f1 100644
--- a/core/modules/block/custom_block/tests/modules/custom_block_test/custom_block_test.module
+++ b/core/modules/block/custom_block/tests/modules/custom_block_test/custom_block_test.module
@@ -89,7 +89,7 @@ function custom_block_test_custom_block_insert(CustomBlock $custom_block) {
 function custom_block_test_menu() {
   $items = array();
   // Add a block-view callback.
-  $items['custom-block/%custom_block'] = array(
+  $items['custom-block/%'] = array(
     'title callback' => 'entity_page_label',
     'title arguments' => array(1),
     'route_name' => 'custom_block_test.custom_block_view',
diff --git a/core/modules/book/book.module b/core/modules/book/book.module
index cd7d714..b0c9964 100644
--- a/core/modules/book/book.module
+++ b/core/modules/book/book.module
@@ -176,7 +176,7 @@ function book_menu() {
     'route_name' => 'book.render',
     'type' => MENU_SUGGESTED_ITEM,
   );
-  $items['node/%node/outline/remove'] = array(
+  $items['node/%/outline/remove'] = array(
     'title' => 'Remove from outline',
     'route_name' => 'book.remove',
   );
diff --git a/core/modules/config/tests/config_test/config_test.module b/core/modules/config/tests/config_test/config_test.module
index 9c0b042..f6bbf3a 100644
--- a/core/modules/config/tests/config_test/config_test.module
+++ b/core/modules/config/tests/config_test/config_test.module
@@ -18,18 +18,18 @@ function config_test_menu() {
     'title' => 'Test configuration',
     'route_name' => 'config_test.list_page',
   );
-  $items['admin/structure/config_test/manage/%config_test'] = array(
+  $items['admin/structure/config_test/manage/%'] = array(
     'route_name' => 'config_test.entity',
   );
-  $items['admin/structure/config_test/manage/%config_test/delete'] = array(
+  $items['admin/structure/config_test/manage/%/delete'] = array(
     'title' => 'Delete',
     'route_name' => 'config_test.entity_delete',
   );
-  $items['admin/structure/config_test/manage/%config_test/enable'] = array(
+  $items['admin/structure/config_test/manage/%/enable'] = array(
     'title' => 'Enable',
     'route_name' => 'config_test.entity_enable',
   );
-  $items['admin/structure/config_test/manage/%config_test/disable'] = array(
+  $items['admin/structure/config_test/manage/%/disable'] = array(
     'title' => 'Disable',
     'route_name' => 'config_test.entity_disable',
   );
diff --git a/core/modules/contact/contact.module b/core/modules/contact/contact.module
index 58e343e..a6638e3 100644
--- a/core/modules/contact/contact.module
+++ b/core/modules/contact/contact.module
@@ -63,7 +63,7 @@ function contact_menu() {
     'description' => 'Create a system contact form and set up categories for the form to use.',
     'route_name' => 'contact.category_list',
   );
-  $items['admin/structure/contact/manage/%contact_category'] = array(
+  $items['admin/structure/contact/manage/%'] = array(
     'title' => 'Edit contact category',
     'route_name' => 'contact.category_edit',
   );
@@ -74,14 +74,14 @@ function contact_menu() {
     'menu_name' => 'footer',
     'type' => MENU_SUGGESTED_ITEM,
   );
-  $items['contact/%contact_category'] = array(
+  $items['contact/%'] = array(
     'title' => 'Contact category form',
     'title callback' => 'entity_page_label',
     'title arguments' => array(1),
     'route_name' => 'contact.site_page_category',
     'type' => MENU_VISIBLE_IN_BREADCRUMB,
   );
-  $items['user/%user/contact'] = array(
+  $items['user/%/contact'] = array(
     'title' => 'Contact',
     'route_name' => 'contact.personal_page',
     'type' => MENU_LOCAL_TASK,
diff --git a/core/modules/field/tests/modules/field_test/field_test.module b/core/modules/field/tests/modules/field_test/field_test.module
index c02a40c..37c39ce 100644
--- a/core/modules/field/tests/modules/field_test/field_test.module
+++ b/core/modules/field/tests/modules/field_test/field_test.module
@@ -41,7 +41,7 @@ function field_test_permission() {
  */
 function field_test_menu() {
   $items = array();
-  $items['test-entity/nested/%entity_test/%entity_test'] = array(
+  $items['test-entity/nested/%/%'] = array(
     'title' => 'Nested entity form',
     'route_name' => 'field_test.entity_nested_form',
   );
diff --git a/core/modules/forum/forum.module b/core/modules/forum/forum.module
index e860181..871a82c 100644
--- a/core/modules/forum/forum.module
+++ b/core/modules/forum/forum.module
@@ -108,7 +108,7 @@ function forum_menu() {
     'title' => 'Forums',
     'route_name' => 'forum.index',
   );
-  $items['forum/%forum'] = array(
+  $items['forum/%'] = array(
     'title' => 'Forums',
     'title callback' => 'entity_page_label',
     'title arguments' => array(1),
@@ -119,15 +119,15 @@ function forum_menu() {
     'description' => 'Control forum hierarchy settings.',
     'route_name' => 'forum.overview',
   );
-  $items['admin/structure/forum/edit/container/%taxonomy_term'] = array(
+  $items['admin/structure/forum/edit/container/%'] = array(
     'title' => 'Edit container',
     'route_name' => 'forum.edit_container',
   );
-  $items['admin/structure/forum/edit/forum/%taxonomy_term'] = array(
+  $items['admin/structure/forum/edit/forum/%'] = array(
     'title' => 'Edit forum',
     'route_name' => 'forum.edit_forum',
   );
-  $items['admin/structure/forum/delete/forum/%taxonomy_term'] = array(
+  $items['admin/structure/forum/delete/forum/%'] = array(
     'title' => 'Delete forum',
     'route_name' => 'forum.delete',
   );
diff --git a/core/modules/image/image.module b/core/modules/image/image.module
index ec12e15..afd142f 100644
--- a/core/modules/image/image.module
+++ b/core/modules/image/image.module
@@ -100,7 +100,7 @@ function image_menu() {
     'description' => 'List the current image styles on the site.',
     'type' => MENU_DEFAULT_LOCAL_TASK,
   );
-  $items['admin/config/media/image-styles/manage/%image_style'] = array(
+  $items['admin/config/media/image-styles/manage/%'] = array(
     'title' => 'Edit style',
     'description' => 'Configure an image style.',
     'route_name' => 'image.style_edit',
@@ -110,7 +110,7 @@ function image_menu() {
     'description' => 'Edit an existing effect within a style.',
     'route_name' => 'image.effect_edit_form',
   );
-  $items['admin/config/media/image-styles/manage/%image_style/effects/%/delete'] = array(
+  $items['admin/config/media/image-styles/manage/%/effects/%/delete'] = array(
     'title' => 'Delete image effect',
     'description' => 'Delete an existing effect from a style.',
     'route_name' => 'image.effect_delete',
diff --git a/core/modules/menu/menu.module b/core/modules/menu/menu.module
index eff3d8d..6e02c2e 100644
--- a/core/modules/menu/menu.module
+++ b/core/modules/menu/menu.module
@@ -80,21 +80,21 @@ function menu_menu() {
     'type' => MENU_LOCAL_TASK,
     'weight' => 100,
   );
-  $items['admin/structure/menu/manage/%menu'] = array(
+  $items['admin/structure/menu/manage/%'] = array(
     'title' => 'Edit menu',
     'route_name' => 'menu.menu_edit',
     'title callback' => 'entity_page_label',
     'title arguments' => array(4),
   );
-  $items['admin/structure/menu/item/%menu_link/edit'] = array(
+  $items['admin/structure/menu/item/%/edit'] = array(
     'title' => 'Edit menu link',
     'route_name' => 'menu.link_edit',
   );
-  $items['admin/structure/menu/item/%menu_link/reset'] = array(
+  $items['admin/structure/menu/item/%/reset'] = array(
     'title' => 'Reset menu link',
     'route_name' => 'menu.link_reset',
   );
-  $items['admin/structure/menu/item/%menu_link/delete'] = array(
+  $items['admin/structure/menu/item/%/delete'] = array(
     'title' => 'Delete menu link',
     'route_name' => 'menu.link_delete',
   );
diff --git a/core/modules/node/node.module b/core/modules/node/node.module
index a860f3f..4c82f0d 100644
--- a/core/modules/node/node.module
+++ b/core/modules/node/node.module
@@ -953,27 +953,27 @@ function node_menu() {
     'title' => 'Add content',
     'route_name' => 'node.add_page',
   );
-  $items['node/add/%node_type'] = array(
+  $items['node/add/%'] = array(
     'description callback' => 'node_type_get_description',
     'description arguments' => array(2),
     'route_name' => 'node.add',
   );
-  $items['node/%node'] = array(
+  $items['node/%'] = array(
     'title callback' => 'node_page_title',
     'title arguments' => array(1),
     // The controller also sets the #title in case the routes' title is
     // overridden by a menu link.
     'route_name' => 'node.view',
   );
-  $items['node/%node/revisions/%node_revision/view'] = array(
+  $items['node/%/revisions/%/view'] = array(
     'title' => 'Revisions',
     'route_name' => 'node.revision_show',
   );
-  $items['node/%node/revisions/%node_revision/revert'] = array(
+  $items['node/%/revisions/%/revert'] = array(
     'title' => 'Revert to earlier revision',
     'route_name' => 'node.revision_revert_confirm',
   );
-  $items['node/%node/revisions/%node_revision/delete'] = array(
+  $items['node/%/revisions/%/delete'] = array(
     'title' => 'Delete earlier revision',
     'route_name' => 'node.revision_delete_confirm',
   );
diff --git a/core/modules/path/path.module b/core/modules/path/path.module
index a965e9d..c4f4527 100644
--- a/core/modules/path/path.module
+++ b/core/modules/path/path.module
@@ -66,11 +66,11 @@ function path_menu() {
     'title' => 'List',
     'type' => MENU_DEFAULT_LOCAL_TASK,
   );
-  $items['admin/config/search/path/edit/%path'] = array(
+  $items['admin/config/search/path/edit/%'] = array(
     'title' => 'Edit alias',
     'route_name' => 'path.admin_edit',
   );
-  $items['admin/config/search/path/delete/%path'] = array(
+  $items['admin/config/search/path/delete/%'] = array(
     'title' => 'Delete alias',
     'route_name' => 'path.delete',
   );
diff --git a/core/modules/picture/picture.module b/core/modules/picture/picture.module
index b9b3b01..58a675f 100644
--- a/core/modules/picture/picture.module
+++ b/core/modules/picture/picture.module
@@ -59,16 +59,16 @@ function picture_menu() {
     'weight' => 10,
     'route_name' => 'picture.mapping_page',
   );
-  $items['admin/config/media/picturemapping/%picture_mapping'] = array(
+  $items['admin/config/media/picturemapping/%'] = array(
     'title' => 'Edit picture mapping',
     'route_name' => 'picture.mapping_page_edit',
   );
-  $items['admin/config/media/picturemapping/%picture_mapping/edit'] = array(
+  $items['admin/config/media/picturemapping/%/edit'] = array(
     'title' => 'Edit',
     'type' => MENU_DEFAULT_LOCAL_TASK,
     'weight' => -10,
   );
-  $items['admin/config/media/picturemapping/%picture_mapping/duplicate'] = array(
+  $items['admin/config/media/picturemapping/%/duplicate'] = array(
     'title' => 'Duplicate picture mapping',
     'route_name' => 'picture.mapping_page_duplicate',
   );
diff --git a/core/modules/shortcut/shortcut.module b/core/modules/shortcut/shortcut.module
index d0594b0..38b4a4d 100644
--- a/core/modules/shortcut/shortcut.module
+++ b/core/modules/shortcut/shortcut.module
@@ -90,17 +90,17 @@ function shortcut_menu() {
     'description' => 'Add and modify shortcut sets.',
     'route_name' => 'shortcut.set_admin',
   );
-  $items['admin/config/user-interface/shortcut/manage/%shortcut_set'] = array(
+  $items['admin/config/user-interface/shortcut/manage/%'] = array(
     'title' => 'Edit shortcuts',
     'route_name' => 'shortcut.set_customize',
     'title callback' => 'entity_page_label',
     'title arguments' => array(5),
   );
-  $items['admin/config/user-interface/shortcut/link/%menu_link'] = array(
+  $items['admin/config/user-interface/shortcut/link/%'] = array(
     'title' => 'Edit shortcut',
     'route_name' => 'shortcut.link_edit',
   );
-  $items['admin/config/user-interface/shortcut/link/%menu_link/delete'] = array(
+  $items['admin/config/user-interface/shortcut/link/%/delete'] = array(
     'title' => 'Delete shortcut',
     'route_name' => 'shortcut.link_delete',
   );
diff --git a/core/modules/system/tests/modules/menu_test/menu_test.module b/core/modules/system/tests/modules/menu_test/menu_test.module
index df5b490..2534a5d 100644
--- a/core/modules/system/tests/modules/menu_test/menu_test.module
+++ b/core/modules/system/tests/modules/menu_test/menu_test.module
@@ -73,10 +73,7 @@ function menu_test_menu() {
     'route_name' => 'menu_test.no_theme_callback',
   );
   // Path containing "exotic" characters.
-  $path = "menu-test/ -._~!$'\"()*@[]?&+%#,;=:" . // "Special" ASCII characters.
-    "%23%25%26%2B%2F%3F" . // Characters that look like a percent-escaped string.
-    "éøïвβ中國書۞"; // Characters from various non-ASCII alphabets.
-  $items[$path] = array(
+  $items['menu-test/%'] = array(
     'title' => '"Exotic" path',
     'route_name' => 'menu_test.exotic_path',
   );
@@ -108,22 +105,22 @@ function menu_test_menu() {
     'type' => MENU_LOCAL_TASK,
     'weight' => 5,
   );
-  $items['menu-test/hidden/menu/manage/%menu'] = array(
+  $items['menu-test/hidden/menu/manage/%'] = array(
     'title' => 'Customize menu',
     'route_name' => 'menu_test.hidden_manage',
   );
-  $items['menu-test/hidden/menu/manage/%menu/list'] = array(
+  $items['menu-test/hidden/menu/manage/%/list'] = array(
     'title' => 'List links',
     'type' => MENU_DEFAULT_LOCAL_TASK,
     'context' => MENU_CONTEXT_PAGE,
   );
-  $items['menu-test/hidden/menu/manage/%menu/edit'] = array(
+  $items['menu-test/hidden/menu/manage/%/edit'] = array(
     'title' => 'Edit menu',
     'route_name' => 'menu_test.hidden_manage_edit',
     'type' => MENU_LOCAL_TASK,
     'context' => MENU_CONTEXT_PAGE,
   );
-  $items['menu-test/hidden/menu/manage/%menu/delete'] = array(
+  $items['menu-test/hidden/menu/manage/%/delete'] = array(
     'title' => 'Delete menu',
     'route_name' => 'menu_test.hidden_manage_delete',
   );
@@ -158,7 +155,6 @@ function menu_test_menu() {
   $items['menu-test/breadcrumb/tasks/first'] = array(
     'title' => 'First',
     'type' => MENU_DEFAULT_LOCAL_TASK,
-    'route_name' => 'menu_test.breadcrumbs_first',
   );
   $items['menu-test/breadcrumb/tasks/second'] = array(
     'title' => 'Second',
@@ -168,7 +164,6 @@ function menu_test_menu() {
   $items['menu-test/breadcrumb/tasks/first/first'] = array(
     'title' => 'First first',
     'type' => MENU_DEFAULT_LOCAL_TASK,
-    'route_name' => 'menu_test.breadcrumbs_first_first',
   );
   $items['menu-test/breadcrumb/tasks/first/second'] = array(
     'title' => 'First second',
@@ -178,7 +173,6 @@ function menu_test_menu() {
   $items['menu-test/breadcrumb/tasks/second/first'] = array(
     'title' => 'Second first',
     'type' => MENU_DEFAULT_LOCAL_TASK,
-    'route_name' => 'menu_test.breadcrumbs_second_first',
   );
   $items['menu-test/breadcrumb/tasks/second/second'] = array(
     'title' => 'Second second',
diff --git a/core/modules/taxonomy/taxonomy.module b/core/modules/taxonomy/taxonomy.module
index c5f6153..24ce58a 100644
--- a/core/modules/taxonomy/taxonomy.module
+++ b/core/modules/taxonomy/taxonomy.module
@@ -241,13 +241,13 @@ function taxonomy_menu() {
     'route_name' => 'taxonomy.vocabulary_list',
   );
 
-  $items['taxonomy/term/%taxonomy_term'] = array(
+  $items['taxonomy/term/%'] = array(
     'title' => 'Taxonomy term',
     'title callback' => 'taxonomy_term_title',
     'title arguments' => array(2),
     'route_name' => 'taxonomy.term_page',
   );
-  $items['taxonomy/term/%taxonomy_term/feed'] = array(
+  $items['taxonomy/term/%/feed'] = array(
     'title' => 'Taxonomy term',
     'title callback' => 'taxonomy_term_title',
     'title arguments' => array(2),
@@ -255,16 +255,16 @@ function taxonomy_menu() {
     'type' => MENU_CALLBACK,
   );
 
-  $items['admin/structure/taxonomy/manage/%taxonomy_vocabulary'] = array(
+  $items['admin/structure/taxonomy/manage/%'] = array(
     'route_name' => 'taxonomy.overview_terms',
     'title callback' => 'entity_page_label',
     'title arguments' => array(4),
   );
-  $items['admin/structure/taxonomy/manage/%taxonomy_vocabulary/list'] = array(
+  $items['admin/structure/taxonomy/manage/%/list'] = array(
     'title' => 'List',
     'type' => MENU_DEFAULT_LOCAL_TASK,
   );
-  $items['admin/structure/taxonomy/manage/%taxonomy_vocabulary/edit'] = array(
+  $items['admin/structure/taxonomy/manage/%/edit'] = array(
     'title' => 'Edit',
     'route_name' => 'taxonomy.vocabulary_edit',
     'type' => MENU_LOCAL_TASK,
diff --git a/core/modules/update/lib/Drupal/update/Tests/UpdateCoreTest.php b/core/modules/update/lib/Drupal/update/Tests/UpdateCoreTest.php
index 7928455..999968a 100644
--- a/core/modules/update/lib/Drupal/update/Tests/UpdateCoreTest.php
+++ b/core/modules/update/lib/Drupal/update/Tests/UpdateCoreTest.php
@@ -256,7 +256,7 @@ public function testLocalActions() {
 
     $this->drupalGet('admin/appearance');
     $this->clickLink(t('Install new theme'));
-    $this->assertUrl('admin/theme/install');
+    $this->assertUrl('admin/appearance/install');
 
     $this->drupalGet('admin/reports/updates');
     $this->clickLink(t('Install new module or theme'));
diff --git a/core/modules/update/lib/Drupal/update/Tests/UpdateUploadTest.php b/core/modules/update/lib/Drupal/update/Tests/UpdateUploadTest.php
index e19fd06..fef6904 100644
--- a/core/modules/update/lib/Drupal/update/Tests/UpdateUploadTest.php
+++ b/core/modules/update/lib/Drupal/update/Tests/UpdateUploadTest.php
@@ -93,24 +93,32 @@ function testUpdateManagerCoreSecurityUpdateMessages() {
     // about core missing a security update.
 
     $this->drupalGet('admin/modules/install');
+    $this->assertResponse(200);
     $this->assertNoText(t('There is a security update available for your version of Drupal.'));
 
     $this->drupalGet('admin/modules/update');
+    $this->assertResponse(200);
     $this->assertNoText(t('There is a security update available for your version of Drupal.'));
 
     $this->drupalGet('admin/appearance/install');
+    $this->assertResponse(200);
     $this->assertNoText(t('There is a security update available for your version of Drupal.'));
 
     $this->drupalGet('admin/appearance/update');
+    $this->assertResponse(200);
     $this->assertNoText(t('There is a security update available for your version of Drupal.'));
 
     $this->drupalGet('admin/reports/updates/install');
+    $this->assertResponse(200);
     $this->assertNoText(t('There is a security update available for your version of Drupal.'));
 
     $this->drupalGet('admin/reports/updates/update');
+    $this->assertResponse(200);
     $this->assertNoText(t('There is a security update available for your version of Drupal.'));
 
     $this->drupalGet('admin/update/ready');
+    $this->assertResponse(200);
     $this->assertNoText(t('There is a security update available for your version of Drupal.'));
   }
+
 }
diff --git a/core/modules/update/update.routing.yml b/core/modules/update/update.routing.yml
index fcfbdd1..38adf41 100644
--- a/core/modules/update/update.routing.yml
+++ b/core/modules/update/update.routing.yml
@@ -63,7 +63,7 @@ update.module_update:
     _access_update_manager: 'TRUE'
 
 update.theme_install:
-  path: '/admin/theme/install'
+  path: '/admin/appearance/install'
   defaults:
     _content: '\Drupal\update\Form\UpdateForm::themeInstall'
   options:
@@ -73,7 +73,7 @@ update.theme_install:
     _access_update_manager: 'TRUE'
 
 update.theme_update:
-  path: '/admin/theme/update'
+  path: '/admin/appearance/update'
   defaults:
     _content: '\Drupal\update\Form\UpdateForm::themeUpdate'
     _title: 'Update'
diff --git a/core/modules/user/tests/modules/user_form_test/user_form_test.module b/core/modules/user/tests/modules/user_form_test/user_form_test.module
index 134804f..d5094b9 100644
--- a/core/modules/user/tests/modules/user_form_test/user_form_test.module
+++ b/core/modules/user/tests/modules/user_form_test/user_form_test.module
@@ -12,7 +12,7 @@
  */
 function user_form_test_menu() {
   $items = array();
-  $items['user_form_test_current_password/%user'] = array(
+  $items['user_form_test_current_password/%'] = array(
     'title' => 'User form test for current password validation',
     'route_name' => 'user_form_test.current_password',
     'type' => MENU_SUGGESTED_ITEM,
diff --git a/core/modules/user/user.module b/core/modules/user/user.module
index 4ee0675..24f01c1 100644
--- a/core/modules/user/user.module
+++ b/core/modules/user/user.module
@@ -782,7 +782,7 @@ function user_menu() {
     'type' => MENU_LOCAL_TASK,
   );
 
-  $items['admin/people/roles/manage/%user_role'] = array(
+  $items['admin/people/roles/manage/%'] = array(
     'title' => 'Edit role',
     'route_name' => 'user.role_edit',
   );
@@ -803,16 +803,16 @@ function user_menu() {
     'route_name' => 'user.account_settings',
   );
 
-  $items['user/%user'] = array(
+  $items['user/%'] = array(
     'title' => 'My account',
     'title callback' => 'user_page_title',
     'title arguments' => array(1),
     'route_name' => 'user.view',
   );
-  $items['user/%user/cancel'] = array(
+  $items['user/%/cancel'] = array(
     'route_name' => 'user.cancel',
   );
-  $items['user/%user/cancel/confirm/%/%'] = array(
+  $items['user/%/cancel/confirm'] = array(
     'title' => 'Confirm account cancellation',
     'route_name' => 'user.cancel_confirm',
   );
@@ -874,17 +874,6 @@ function user_admin_paths() {
 }
 
 /**
- * Returns $arg or the user ID of the current user if $arg is '%' or empty.
- *
- * Deprecated. Use %user_uid_optional instead.
- *
- * @todo D8: Remove.
- */
-function user_uid_only_optional_to_arg($arg) {
-  return user_uid_optional_to_arg($arg);
-}
-
-/**
  * Load either a specified or the current user account.
  *
  * @param $uid
@@ -905,18 +894,6 @@ function user_uid_optional_load($uid = NULL) {
 }
 
 /**
- * Returns $arg or the user ID of the current user if $arg is '%' or empty.
- *
- * @todo rethink the naming of this in Drupal 8.
- */
-function user_uid_optional_to_arg($arg) {
-  // Give back the current user uid when called from eg. tracker, aka.
-  // with an empty arg. Also use the current user uid when called from
-  // the menu with a % for the current account link.
-  return empty($arg) || $arg == '%' ? $GLOBALS['user']->id() : $arg;
-}
-
-/**
  * Menu item title callback for the 'user' path.
  *
  * Anonymous users should see a title based on the requested page, but