core/misc/autocomplete.js                          |  1 -
 .../src/Plugin/Field/FieldWidget/LinkWidget.php    | 36 +++++++++++++---------
 .../system/src/Tests/Menu/BreadcrumbTest.php       |  2 +-
 3 files changed, 23 insertions(+), 16 deletions(-)

diff --git a/core/misc/autocomplete.js b/core/misc/autocomplete.js
index d9f230d..b4e4123 100644
--- a/core/misc/autocomplete.js
+++ b/core/misc/autocomplete.js
@@ -62,7 +62,6 @@
     var options = autocomplete.options;
     var term = autocomplete.extractLastTerm(event.target.value);
     // Abort search if the first character is in firstCharacterBlacklist.
-    debugger;
     if (term.length > 0 && options.firstCharacterBlacklist.indexOf(term[0]) !== -1) {
       return false;
     }
diff --git a/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php b/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
index 24a6237..486db63 100644
--- a/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
+++ b/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
@@ -44,7 +44,11 @@ public static function defaultSettings() {
   }
 
   /**
-   * Gets the URI without the 'user-path:' scheme, for display while editing.
+   * Gets the URI without the 'user-path:' or 'entity:' scheme.
+   *
+   * The following two forms of URIs are transformed:
+   * - 'entity:' URIs: to entity autocomplete ("label (entity id)") strings;
+   * - 'user-path:' URIs: the scheme is stripped.
    *
    * This method is the inverse of ::getUserEnteredStringAsUri().
    *
@@ -94,7 +98,9 @@ protected static function getUriAsDisplayableString($uri) {
   /**
    * Gets the user-entered string as a URI.
    *
-   * Schemeless URIs are treated as 'user-path:' URIs.
+   * The following two forms of input are mapped to URIs:
+   * - entity autocomplete ("label (entity id)") strings: to 'entity:' URIs;
+   * - strings without a detectable scheme: to 'user-path:' URIs.
    *
    * This method is the inverse of ::getUriAsDisplayableString().
    *
@@ -107,22 +113,24 @@ protected static function getUriAsDisplayableString($uri) {
    * @see getUriAsDisplayableString()
    */
   protected static function getUserEnteredStringAsUri($string) {
+    // By default, assume the entered string is an URI.
+    $uri = $string;
+
+    // Detect entity autocomplete string, map to 'entity:' URI.
     $entity_id = EntityAutocomplete::extractEntityIdFromAutocompleteInput($string);
     if ($entity_id !== NULL) {
-      $string = 'entity:node/' . $entity_id;
+      // @todo Support entity types other than 'node'.
+      $uri = 'entity:node/' . $entity_id;
     }
-
-    if (!empty($string)) {
-      // Users can enter relative URLs, but we need a valid URI, so add an
-      // explicit scheme when necessary.
-      if (parse_url($string, PHP_URL_SCHEME) === NULL) {
-        // @todo The ltrim() call here will become obsolete as soon as
-        //    https://www.drupal.org/node/241764 lands; see earlier todo for
-        //    more info.
-        $string = 'user-path:' . ltrim($string, '/');
-      }
+    // Detect a schemeless string, map to 'user-path:' URI.
+    elseif (!empty($string) && parse_url($string, PHP_URL_SCHEME) === NULL) {
+      // @todo The ltrim() call here will become obsolete as soon as
+      //    https://www.drupal.org/node/241764 lands; see earlier todo for
+      //    more info.
+      $uri = 'user-path:' . ltrim($string, '/');
     }
-    return $string;
+
+    return $uri;
   }
 
   /**
diff --git a/core/modules/system/src/Tests/Menu/BreadcrumbTest.php b/core/modules/system/src/Tests/Menu/BreadcrumbTest.php
index 1755091..3048e37 100644
--- a/core/modules/system/src/Tests/Menu/BreadcrumbTest.php
+++ b/core/modules/system/src/Tests/Menu/BreadcrumbTest.php
@@ -248,7 +248,7 @@ function testBreadCrumbs() {
       $menu_links = entity_load_multiple_by_properties('menu_link_content', array(
         'title' => $edit['title[0][value]'],
         // @todo Use link.uri once https://www.drupal.org/node/2391217 is in.
-        'link__uri' => 'user-path:/taxonomy/term/' . $term->id(),
+        'link__uri' => 'user-path:taxonomy/term/' . $term->id(),
       ));
       $tags[$name]['link'] = reset($menu_links);
       $parent_mlid = $tags[$name]['link']->getPluginId();