diff --git a/core/core.library.yml b/core/core.libraries.yml
similarity index 99%
rename from core/core.library.yml
rename to core/core.libraries.yml
index 126e535..4e80798 100644
--- a/core/core.library.yml
+++ b/core/core.libraries.yml
@@ -1,3 +1,5 @@
+# All libraries are defined in alphabetical order.
+
 backbone:
   remote: https://github.com/jashkenas/backbone
   version: 1.1.0
diff --git a/core/includes/common.inc b/core/includes/common.inc
index 6ad81e5..34775a4 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -2781,7 +2781,7 @@ function drupal_get_library($extension, $name = NULL) {
         $extension_type = 'theme';
       }
     }
-    $library_file = DRUPAL_ROOT . '/' . $path . '/' . $extension . '.library.yml';
+    $library_file = DRUPAL_ROOT . '/' . $path . '/' . $extension . '.libraries.yml';
 
     if ($library_file && file_exists($library_file)) {
       $parser = new Parser();
@@ -2846,8 +2846,11 @@ function drupal_get_library($extension, $name = NULL) {
           if (!isset($options['type'])) {
             $options['type'] = 'file';
           }
-          // Determine the file asset URI, unless explicitly marked as external.
-          if ($options['type'] != 'external') {
+          if ($options['type'] == 'external') {
+            $options['data'] = $source;
+          }
+          // Determine the file asset URI.
+          else {
             if ($source[0] === '/') {
               // An absolute path maps to DRUPAL_ROOT / base_path().
               if ($source[1] !== '/') {
@@ -2889,7 +2892,10 @@ function drupal_get_library($extension, $name = NULL) {
         }
       }
     }
-    cache()->set('library:info:' . $extension, $libraries[$extension], CacheBackendInterface::CACHE_PERMANENT, array('extension' => array(TRUE, $extension)));
+    cache()->set('library:info:' . $extension, $libraries[$extension], CacheBackendInterface::CACHE_PERMANENT, array(
+      'extension' => array(TRUE, $extension),
+      'library_info' => array(TRUE),
+    ));
   }
 
   if (isset($name)) {
diff --git a/core/modules/block/block.library.yml b/core/modules/block/block.libraries.yml
similarity index 100%
rename from core/modules/block/block.library.yml
rename to core/modules/block/block.libraries.yml
diff --git a/core/modules/book/book.library.yml b/core/modules/book/book.libraries.yml
similarity index 100%
rename from core/modules/book/book.library.yml
rename to core/modules/book/book.libraries.yml
diff --git a/core/modules/ckeditor/ckeditor.library.yml b/core/modules/ckeditor/ckeditor.libraries.yml
similarity index 100%
rename from core/modules/ckeditor/ckeditor.library.yml
rename to core/modules/ckeditor/ckeditor.libraries.yml
diff --git a/core/modules/color/color.library.yml b/core/modules/color/color.libraries.yml
similarity index 100%
rename from core/modules/color/color.library.yml
rename to core/modules/color/color.libraries.yml
diff --git a/core/modules/comment/comment.library.yml b/core/modules/comment/comment.libraries.yml
similarity index 100%
rename from core/modules/comment/comment.library.yml
rename to core/modules/comment/comment.libraries.yml
diff --git a/core/modules/config_translation/config_translation.library.yml b/core/modules/config_translation/config_translation.libraries.yml
similarity index 100%
rename from core/modules/config_translation/config_translation.library.yml
rename to core/modules/config_translation/config_translation.libraries.yml
diff --git a/core/modules/content_translation/content_translation.library.yml b/core/modules/content_translation/content_translation.libraries.yml
similarity index 100%
rename from core/modules/content_translation/content_translation.library.yml
rename to core/modules/content_translation/content_translation.libraries.yml
diff --git a/core/modules/contextual/contextual.library.yml b/core/modules/contextual/contextual.libraries.yml
similarity index 100%
rename from core/modules/contextual/contextual.library.yml
rename to core/modules/contextual/contextual.libraries.yml
diff --git a/core/modules/edit/edit.library.yml b/core/modules/edit/edit.libraries.yml
similarity index 100%
rename from core/modules/edit/edit.library.yml
rename to core/modules/edit/edit.libraries.yml
diff --git a/core/modules/editor/editor.library.yml b/core/modules/editor/editor.libraries.yml
similarity index 100%
rename from core/modules/editor/editor.library.yml
rename to core/modules/editor/editor.libraries.yml
diff --git a/core/modules/field_ui/field_ui.library.yml b/core/modules/field_ui/field_ui.libraries.yml
similarity index 100%
rename from core/modules/field_ui/field_ui.library.yml
rename to core/modules/field_ui/field_ui.libraries.yml
diff --git a/core/modules/file/file.library.yml b/core/modules/file/file.libraries.yml
similarity index 100%
rename from core/modules/file/file.library.yml
rename to core/modules/file/file.libraries.yml
diff --git a/core/modules/filter/filter.library.yml b/core/modules/filter/filter.libraries.yml
similarity index 100%
rename from core/modules/filter/filter.library.yml
rename to core/modules/filter/filter.libraries.yml
diff --git a/core/modules/forum/forum.library.yml b/core/modules/forum/forum.libraries.yml
similarity index 100%
rename from core/modules/forum/forum.library.yml
rename to core/modules/forum/forum.libraries.yml
diff --git a/core/modules/history/history.library.yml b/core/modules/history/history.libraries.yml
similarity index 100%
rename from core/modules/history/history.library.yml
rename to core/modules/history/history.libraries.yml
diff --git a/core/modules/language/language.library.yml b/core/modules/language/language.libraries.yml
similarity index 100%
rename from core/modules/language/language.library.yml
rename to core/modules/language/language.libraries.yml
diff --git a/core/modules/locale/locale.library.yml b/core/modules/locale/locale.libraries.yml
similarity index 100%
rename from core/modules/locale/locale.library.yml
rename to core/modules/locale/locale.libraries.yml
diff --git a/core/modules/menu/menu.library.yml b/core/modules/menu/menu.libraries.yml
similarity index 100%
rename from core/modules/menu/menu.library.yml
rename to core/modules/menu/menu.libraries.yml
diff --git a/core/modules/node/node.library.yml b/core/modules/node/node.libraries.yml
similarity index 100%
rename from core/modules/node/node.library.yml
rename to core/modules/node/node.libraries.yml
diff --git a/core/modules/path/path.library.yml b/core/modules/path/path.libraries.yml
similarity index 100%
rename from core/modules/path/path.library.yml
rename to core/modules/path/path.libraries.yml
diff --git a/core/modules/picture/picture.library.yml b/core/modules/picture/picture.libraries.yml
similarity index 100%
rename from core/modules/picture/picture.library.yml
rename to core/modules/picture/picture.libraries.yml
diff --git a/core/modules/shortcut/shortcut.library.yml b/core/modules/shortcut/shortcut.libraries.yml
similarity index 100%
rename from core/modules/shortcut/shortcut.library.yml
rename to core/modules/shortcut/shortcut.libraries.yml
diff --git a/core/modules/simpletest/simpletest.library.yml b/core/modules/simpletest/simpletest.libraries.yml
similarity index 100%
rename from core/modules/simpletest/simpletest.library.yml
rename to core/modules/simpletest/simpletest.libraries.yml
diff --git a/core/modules/statistics/statistics.library.yml b/core/modules/statistics/statistics.libraries.yml
similarity index 100%
rename from core/modules/statistics/statistics.library.yml
rename to core/modules/statistics/statistics.libraries.yml
diff --git a/core/modules/system/system.library.yml b/core/modules/system/system.libraries.yml
similarity index 100%
rename from core/modules/system/system.library.yml
rename to core/modules/system/system.libraries.yml
diff --git a/core/modules/system/tests/modules/common_test/common_test.library.yml b/core/modules/system/tests/modules/common_test/common_test.libraries.yml
similarity index 100%
rename from core/modules/system/tests/modules/common_test/common_test.library.yml
rename to core/modules/system/tests/modules/common_test/common_test.libraries.yml
diff --git a/core/modules/taxonomy/taxonomy.library.yml b/core/modules/taxonomy/taxonomy.libraries.yml
similarity index 100%
rename from core/modules/taxonomy/taxonomy.library.yml
rename to core/modules/taxonomy/taxonomy.libraries.yml
diff --git a/core/modules/text/text.library.yml b/core/modules/text/text.libraries.yml
similarity index 100%
rename from core/modules/text/text.library.yml
rename to core/modules/text/text.libraries.yml
diff --git a/core/modules/toolbar/toolbar.library.yml b/core/modules/toolbar/toolbar.libraries.yml
similarity index 100%
rename from core/modules/toolbar/toolbar.library.yml
rename to core/modules/toolbar/toolbar.libraries.yml
diff --git a/core/modules/tour/tour.library.yml b/core/modules/tour/tour.libraries.yml
similarity index 100%
rename from core/modules/tour/tour.library.yml
rename to core/modules/tour/tour.libraries.yml
diff --git a/core/modules/update/update.library.yml b/core/modules/update/update.libraries.yml
similarity index 100%
rename from core/modules/update/update.library.yml
rename to core/modules/update/update.libraries.yml
diff --git a/core/modules/user/user.library.yml b/core/modules/user/user.libraries.yml
similarity index 100%
rename from core/modules/user/user.library.yml
rename to core/modules/user/user.libraries.yml
diff --git a/core/modules/views/views.library.yml b/core/modules/views/views.libraries.yml
similarity index 100%
rename from core/modules/views/views.library.yml
rename to core/modules/views/views.libraries.yml
diff --git a/core/modules/views_ui/views_ui.library.yml b/core/modules/views_ui/views_ui.libraries.yml
similarity index 100%
rename from core/modules/views_ui/views_ui.library.yml
rename to core/modules/views_ui/views_ui.libraries.yml
diff --git a/core/themes/bartik/bartik.library.yml b/core/themes/bartik/bartik.libraries.yml
similarity index 100%
rename from core/themes/bartik/bartik.library.yml
rename to core/themes/bartik/bartik.libraries.yml
diff --git a/core/themes/seven/seven.library.yml b/core/themes/seven/seven.libraries.yml
similarity index 100%
rename from core/themes/seven/seven.library.yml
rename to core/themes/seven/seven.libraries.yml