diff --git a/core/modules/file/file.field.inc b/core/modules/file/file.field.inc
index 6c06575..bbfc2b2 100644
--- a/core/modules/file/file.field.inc
+++ b/core/modules/file/file.field.inc
@@ -10,27 +10,6 @@
 use Drupal\Core\Render\Element;
 
 /**
- * Returns HTML for an individual file upload widget.
- *
- * Default template: file-widget.html.twig.
- *
- * @param array $variables
- *   An associative array containing:
- *   - element: A render element representing the file.
- */
-function template_preprocess_file_widget(&$variables) {
-  $element = $variables['element'];
-  if (!empty($element['fids']['#value'])) {
-    // Add the file size after the file name.
-    $file = reset($element['#files']);
-    $element['file_' . $file->id()]['filename']['#suffix'] = ' <span class="file-size">(' . format_size($file->getSize()) . ')</span> ';
-  }
-  $variables['element'] = $element;
-  // The "js-form-managed-file" class is required for proper Ajax functionality.
-  $variables['attributes'] = array('class' => array('file-widget', 'js-form-managed-file', 'form-managed-file', 'clearfix'));
-}
-
-/**
  * Prepares variables for multi file form widget templates.
  *
  * Default template: file-widget-multiple.html.twig.
diff --git a/core/modules/file/file.module b/core/modules/file/file.module
index d48b232..26c35ac 100644
--- a/core/modules/file/file.module
+++ b/core/modules/file/file.module
@@ -555,10 +555,6 @@ function file_theme() {
     ),
 
     // From file.field.inc.
-    'file_widget' => array(
-      'render element' => 'element',
-      'file' => 'file.field.inc',
-    ),
     'file_widget_multiple' => array(
       'render element' => 'element',
       'file' => 'file.field.inc',
diff --git a/core/modules/file/src/Plugin/Field/FieldWidget/FileWidget.php b/core/modules/file/src/Plugin/Field/FieldWidget/FileWidget.php
index 6634a5f..3570c35 100644
--- a/core/modules/file/src/Plugin/Field/FieldWidget/FileWidget.php
+++ b/core/modules/file/src/Plugin/Field/FieldWidget/FileWidget.php
@@ -370,11 +370,6 @@ public static function process($element, FormStateInterface $form_state, $form)
     $item = $element['#value'];
     $item['fids'] = $element['fids']['#value'];
 
-    // Prevent the file widget from overriding the image widget.
-    if (!isset($element['#theme'])) {
-      $element['#theme'] = 'file_widget';
-    }
-
     // Add the display field if enabled.
     if ($element['#display_field']) {
       $element['display'] = array(
diff --git a/core/modules/file/templates/file-widget.html.twig b/core/modules/file/templates/file-widget.html.twig
deleted file mode 100644
index 892ed3d..0000000
--- a/core/modules/file/templates/file-widget.html.twig
+++ /dev/null
@@ -1,17 +0,0 @@
-{#
-/**
- * @file
- * Default theme implementation to display a file widget.
- *
- * Available variables:
- * - element: Form element for the managed file.
- * - attributes: Remaining HTML attributes for the containing element.
- *
- * @see template_preprocess_file_widget()
- *
- * @ingroup themeable
- */
-#}
-<div{{ attributes }}>
-  {{ element }}
-</div>
diff --git a/core/themes/classy/templates/content-edit/file-widget.html.twig b/core/themes/classy/templates/content-edit/file-widget.html.twig
deleted file mode 100644
index 23d03a1..0000000
--- a/core/themes/classy/templates/content-edit/file-widget.html.twig
+++ /dev/null
@@ -1,16 +0,0 @@
-{#
-/**
- * @file
- * Theme override to display a file widget.
- *
- * Available variables:
- * - element: Form element for the managed file.
- * - attributes: Remaining HTML attributes for the containing element.
- *
- * @see template_preprocess_file_widget()
- */
-#}
-{{ attach_library('classy/file') }}
-<div{{ attributes }}>
-  {{ element }}
-</div>