diff --git a/core/modules/editor/editor.module b/core/modules/editor/editor.module
index 851bdbb679a76d7a2c7458ca2c4cf38d2b5caedc..2a052dce29bdb9532d09cfc0fda6c0352ead17a5 100644
--- a/core/modules/editor/editor.module
+++ b/core/modules/editor/editor.module
@@ -453,60 +453,6 @@ function _editor_delete_file_usage(array $uuids, EntityInterface $entity, $count
   }
 }
 
-/**
- * Implements hook_file_download().
- *
- * @see file_file_download()
- * @see file_get_file_references()
- */
-function editor_file_download($uri) {
-  // Get the file record based on the URI. If not in the database just return.
-  /** @var \Drupal\file\FileInterface[] $files */
-  $files = \Drupal::entityTypeManager()
-    ->getStorage('file')
-    ->loadByProperties(['uri' => $uri]);
-  if (count($files)) {
-    foreach ($files as $item) {
-      // Since some database servers sometimes use a case-insensitive comparison
-      // by default, double check that the filename is an exact match.
-      if ($item->getFileUri() === $uri) {
-        $file = $item;
-        break;
-      }
-    }
-  }
-  if (!isset($file)) {
-    return;
-  }
-
-  // Temporary files are handled by file_file_download(), so nothing to do here
-  // about them.
-  // @see file_file_download()
-
-  // Find out if any editor-backed field contains the file.
-  $usage_list = \Drupal::service('file.usage')->listUsage($file);
-
-  // Stop processing if there are no references in order to avoid returning
-  // headers for files controlled by other modules. Make an exception for
-  // temporary files where the host entity has not yet been saved (for example,
-  // an image preview on a node creation form) in which case, allow download by
-  // the file's owner.
-  if (empty($usage_list['editor']) && ($file->isPermanent() || $file->getOwnerId() != \Drupal::currentUser()->id())) {
-    return;
-  }
-
-  // Editor.module MUST NOT call $file->access() here (like file_file_download()
-  // does) as checking the 'download' access to a file entity would end up in
-  // FileAccessControlHandler->checkAccess() and ->getFileReferences(), which
-  // calls file_get_file_references(). This latter one would allow downloading
-  // files only handled by the file.module, which is exactly not the case right
-  // here.
-
-  // Access is granted.
-  $headers = file_get_content_headers($file);
-  return $headers;
-}
-
 /**
  * Finds all files referenced (data-entity-uuid) by formatted text fields.
  *
diff --git a/core/modules/editor/src/Tests/EditorPrivateFileReferenceFilterTest.php b/core/modules/editor/src/Tests/EditorPrivateFileReferenceFilterTest.php
deleted file mode 100644
index b5ff6db0306b7acf7bebb321e0c874ed0b9df09a..0000000000000000000000000000000000000000
--- a/core/modules/editor/src/Tests/EditorPrivateFileReferenceFilterTest.php
+++ /dev/null
@@ -1,69 +0,0 @@
-<?php
-
-namespace Drupal\editor\Tests;
-
-use Drupal\file\Entity\File;
-use Drupal\simpletest\WebTestBase;
-
-/**
- * Tests Editor module's file reference filter with private files.
- *
- * @group editor
- */
-class EditorPrivateFileReferenceFilterTest extends WebTestBase {
-
-  /**
-   * Modules to enable.
-   *
-   * @var array
-   */
-  public static $modules = [
-    // Needed for the config: this is the only module in core that utilizes the
-    // functionality in editor.module to be tested, and depends on that.
-    'ckeditor',
-    // Depends on filter.module (indirectly).
-    'node',
-    // Pulls in the config we're using during testing which create a text format
-    // - with the filter_html_image_secure filter DISABLED,
-    // - with the editor set to CKEditor,
-    // - with drupalimage.image_upload.scheme set to 'private',
-    // - with drupalimage.image_upload.directory set to ''.
-    'editor_private_test',
-  ];
-
-  /**
-   * Tests the editor file reference filter with private files.
-   */
-  function testEditorPrivateFileReferenceFilter() {
-    // Create a content type with a body field.
-    $this->drupalCreateContentType(['type' => 'page', 'name' => 'Basic page']);
-
-    // Create a file in the 'private:// ' stream.
-    $filename = 'test.png';
-    $src = '/system/files/' . $filename;
-
-    $file = File::create([
-      'uri' => 'private://' . $filename,
-      'status' => FILE_STATUS_PERMANENT,
-    ]);
-    // Create the file itself.
-    file_put_contents($file->getFileUri(), $this->randomString());
-    $file->save();
-
-    // Create a node with its body field properly pointing to the just-created
-    // file.
-    $node = $this->drupalCreateNode([
-      'type' => 'page',
-      'body' => [
-        'value' => '<img alt="alt" data-entity-type="file" data-entity-uuid="' . $file->uuid() . '" src="' . $src . '" />',
-        'format' => 'private_images',
-      ],
-    ]);
-    $this->drupalGet('/node/' . $node->id());
-
-    // Do the actual test. The image should be visible for anonymous.
-    $this->drupalGet($src);
-    $this->assertResponse(200, 'Image is downloadable as anonymous.');
-  }
-
-}
diff --git a/core/modules/editor/tests/editor_private_test/config/install/editor.editor.private_images.yml b/core/modules/editor/tests/editor_private_test/config/install/editor.editor.private_images.yml
deleted file mode 100644
index 2de126a1cea6c65955d97175fe71a24b35bc6816..0000000000000000000000000000000000000000
--- a/core/modules/editor/tests/editor_private_test/config/install/editor.editor.private_images.yml
+++ /dev/null
@@ -1,34 +0,0 @@
-format: private_images
-status: true
-langcode: en
-editor: ckeditor
-settings:
-  toolbar:
-    rows:
-      -
-        -
-          name: Media
-          items:
-            - DrupalImage
-        -
-          name: Tools
-          items:
-            - Source
-  plugins:
-    language:
-      language_list: un
-    stylescombo:
-      styles: ''
-image_upload:
-  status: true
-  scheme: private
-  directory: ''
-  max_size: ''
-  max_dimensions:
-    width: null
-    height: null
-dependencies:
-  config:
-    - filter.format.private_images
-  module:
-    - ckeditor
diff --git a/core/modules/editor/tests/editor_private_test/config/install/filter.format.private_images.yml b/core/modules/editor/tests/editor_private_test/config/install/filter.format.private_images.yml
deleted file mode 100644
index 261bd901797a40eb411add76527f1af64b4351fb..0000000000000000000000000000000000000000
--- a/core/modules/editor/tests/editor_private_test/config/install/filter.format.private_images.yml
+++ /dev/null
@@ -1,23 +0,0 @@
-format: private_images
-name: 'Private images'
-status: true
-langcode: en
-filters:
-  editor_file_reference:
-    id: editor_file_reference
-    provider: editor
-    status: true
-    weight: 0
-    settings: {  }
-  filter_html:
-    id: filter_html
-    provider: filter
-    status: false
-    weight: -10
-    settings:
-      allowed_html: '<img src alt data-entity-type data-entity-uuid>'
-      filter_html_help: true
-      filter_html_nofollow: false
-dependencies:
-  module:
-    - editor
diff --git a/core/modules/editor/tests/editor_private_test/editor_private_test.info.yml b/core/modules/editor/tests/editor_private_test/editor_private_test.info.yml
deleted file mode 100644
index 474fda67228be1f6ca278900e7468981e789a579..0000000000000000000000000000000000000000
--- a/core/modules/editor/tests/editor_private_test/editor_private_test.info.yml
+++ /dev/null
@@ -1,9 +0,0 @@
-name: 'Text Editor Private test'
-type: module
-description: 'Support module for the Text Editor Private module tests.'
-core: 8.x
-package: Testing
-version: VERSION
-dependencies:
-  - filter
-  - ckeditor