diff -u b/core/lib/Drupal/Core/Url.php b/core/lib/Drupal/Core/Url.php
--- b/core/lib/Drupal/Core/Url.php
+++ b/core/lib/Drupal/Core/Url.php
@@ -24,17 +24,6 @@
   use DependencySerializationTrait;
 
   /**
-   * Scheme for URIs from user input.
-   *
-   * To create a URL for paths from user input that may or may not correspond
-   * to a valid Drupal route, use Url::fromUserInput().
-   *
-   * @see \Drupal\Core\Url::fromUserInput()
-   * @see \Drupal\Core\Url::fromInternalUri()
-   */
-   const SCHEME_INTERNAL = 'internal';
-
-  /**
    * The URL generator.
    *
    * @var \Drupal\Core\Routing\UrlGeneratorInterface
@@ -233,7 +222,7 @@
     if ((strpos($path, '/') !== 0) && (strpos($path, '#') !== 0) && (strpos($path, '?') !== 0)) {
       throw new \InvalidArgumentException(String::format('The path @path is not valid as user input. User-input paths must begin with one of the following characters: / # ?', ['@path' => $path]));
     }
-    return static::fromUri(static::SCHEME_INTERNAL . ':' . $path, $options);
+    return static::fromUri('internal:' . $path, $options);
   }
 
   /**
@@ -320,7 +309,7 @@
     if ($uri_parts['scheme'] === 'entity') {
       $url = static::fromEntityUri($uri_parts, $uri_options, $uri);
     }
-    elseif ($uri_parts['scheme'] === static::SCHEME_INTERNAL) {
+    elseif ($uri_parts['scheme'] === 'internal') {
       $url = static::fromInternalUri($uri_parts, $uri_options);
     }
     elseif ($uri_parts['scheme'] === 'route') {
diff -u b/core/modules/link/src/Plugin/Field/FieldFormatter/LinkFormatter.php b/core/modules/link/src/Plugin/Field/FieldFormatter/LinkFormatter.php
--- b/core/modules/link/src/Plugin/Field/FieldFormatter/LinkFormatter.php
+++ b/core/modules/link/src/Plugin/Field/FieldFormatter/LinkFormatter.php
@@ -210,7 +210,7 @@
           // attribute.
           // @todo Does RDF need a URL rather than an internal URI here?
           // @see \Drupal\rdf\Tests\Field\LinkFieldRdfaTest.
-          $content = str_replace(Url::SCHEME_INTERNAL . ':/', '', $item->uri);
+          $content = str_replace('internal:/', '', $item->uri);
           $item->_attributes += array('content' => $content);
         }
       }
diff -u b/core/modules/menu_link_content/menu_link_content.module b/core/modules/menu_link_content/menu_link_content.module
--- b/core/modules/menu_link_content/menu_link_content.module
+++ b/core/modules/menu_link_content/menu_link_content.module
@@ -58,7 +58,7 @@
   /** @var \Drupal\menu_link_content\MenuLinkContentInterface[] $entities */
   $entities = \Drupal::entityManager()
     ->getStorage('menu_link_content')
-    ->loadByProperties(['link.uri' => Url::SCHEME_INTERNAL . ':/' . $path]);
+    ->loadByProperties(['link.uri' => 'internal:/' . $path]);
   foreach ($entities as $menu_link) {
     $menu_link_manager->updateDefinition($menu_link->getPluginId(), $menu_link->getPluginDefinition(), FALSE);
   }
diff -u b/core/modules/menu_link_content/src/Entity/MenuLinkContent.php b/core/modules/menu_link_content/src/Entity/MenuLinkContent.php
--- b/core/modules/menu_link_content/src/Entity/MenuLinkContent.php
+++ b/core/modules/menu_link_content/src/Entity/MenuLinkContent.php
@@ -187,7 +187,7 @@
   public function preSave(EntityStorageInterface $storage) {
     parent::preSave($storage);
 
-    if (parse_url($this->link->uri, PHP_URL_SCHEME) === Url::SCHEME_INTERNAL) {
+    if (parse_url($this->link->uri, PHP_URL_SCHEME) === 'internal') {
       $this->setRequiresRediscovery(TRUE);
     }
     else {
diff -u b/core/modules/migrate_drupal/src/Plugin/migrate/process/d6/UserPathUri.php b/core/modules/migrate_drupal/src/Plugin/migrate/process/d6/UserPathUri.php
--- b/core/modules/migrate_drupal/src/Plugin/migrate/process/d6/UserPathUri.php
+++ b/core/modules/migrate_drupal/src/Plugin/migrate/process/d6/UserPathUri.php
@@ -28,7 +28,7 @@
     list($path) = $value;
 
     if (parse_url($path, PHP_URL_SCHEME) === NULL) {
-      return Url::SCHEME_INTERNAL . ':/' . $path;
+      return 'internal:/' . $path;
     }
     return $path;
   }