diff --git a/core/lib/Drupal/Core/File/file.api.php b/core/lib/Drupal/Core/File/file.api.php
index 6c5236fec9..26501ff8a7 100644
--- a/core/lib/Drupal/Core/File/file.api.php
+++ b/core/lib/Drupal/Core/File/file.api.php
@@ -108,8 +108,9 @@ function hook_file_url_alter(&$uri) {
 /**
  * Alter MIME type mappings used to determine MIME type from a file extension.
  *
- * Invoked by \Drupal\Core\File\MimeType\ExtensionMimeTypeGuesser::guess(). It
- * is used to allow modules to add to or modify the default mapping from
+ * Invoked by
+ * \Drupal\Core\File\MimeType\ExtensionMimeTypeGuesser::guessMimeType(). It is
+ * used to allow modules to add to or modify the default mapping from
  * \Drupal\Core\File\MimeType\ExtensionMimeTypeGuesser::$defaultMapping.
  *
  * @param $mapping
@@ -117,7 +118,7 @@ function hook_file_url_alter(&$uri) {
  *   The array has 'mimetypes' and 'extensions' elements, each of which is an
  *   array.
  *
- * @see \Drupal\Core\File\MimeType\ExtensionMimeTypeGuesser::guess()
+ * @see \Drupal\Core\File\MimeType\ExtensionMimeTypeGuesser::guessMimeType()
  * @see \Drupal\Core\File\MimeType\ExtensionMimeTypeGuesser::$defaultMapping
  */
 function hook_file_mimetype_mapping_alter(&$mapping) {
diff --git a/core/modules/file/file.module b/core/modules/file/file.module
index 0f8416b369..75a163a878 100644
--- a/core/modules/file/file.module
+++ b/core/modules/file/file.module
@@ -945,7 +945,7 @@ function _file_save_upload_single(\SplFileInfo $file_info, $form_field_name, $va
     'uri' => $file_info->getRealPath(),
     'filesize' => $file_info->getSize(),
   ];
-  $values['filemime'] = \Drupal::service('file.mime_type.guesser')->guess($values['filename']);
+  $values['filemime'] = \Drupal::service('file.mime_type.guesser')->guessMimeType($values['filename']);
   $file = File::create($values);
 
   $extensions = '';
diff --git a/core/modules/file/src/Entity/File.php b/core/modules/file/src/Entity/File.php
index 6332ca32aa..333219e0f5 100644
--- a/core/modules/file/src/Entity/File.php
+++ b/core/modules/file/src/Entity/File.php
@@ -160,7 +160,7 @@ public static function preCreate(EntityStorageInterface $storage, array &$values
 
     // Automatically detect filemime if not set.
     if (!isset($values['filemime']) && isset($values['uri'])) {
-      $values['filemime'] = \Drupal::service('file.mime_type.guesser')->guess($values['uri']);
+      $values['filemime'] = \Drupal::service('file.mime_type.guesser')->guessMimeType($values['uri']);
     }
   }
 
diff --git a/core/modules/file/src/Plugin/Field/FieldFormatter/FileMediaFormatterBase.php b/core/modules/file/src/Plugin/Field/FieldFormatter/FileMediaFormatterBase.php
index 72192d6295..264914c1e1 100644
--- a/core/modules/file/src/Plugin/Field/FieldFormatter/FileMediaFormatterBase.php
+++ b/core/modules/file/src/Plugin/Field/FieldFormatter/FileMediaFormatterBase.php
@@ -75,12 +75,12 @@ public static function isApplicable(FieldDefinitionInterface $field_definition)
     if (!parent::isApplicable($field_definition)) {
       return FALSE;
     }
-    /** @var \Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesserInterface $extension_mime_type_guesser */
+    /** @var \Symfony\Component\Mime\MimeTypeGuesserInterface $extension_mime_type_guesser */
     $extension_mime_type_guesser = \Drupal::service('file.mime_type.guesser.extension');
     $extension_list = array_filter(preg_split('/\s+/', $field_definition->getSetting('file_extensions')));
 
     foreach ($extension_list as $extension) {
-      $mime_type = $extension_mime_type_guesser->guess('fakedFile.' . $extension);
+      $mime_type = $extension_mime_type_guesser->guessMimeType('fakedFile.' . $extension);
 
       if (static::mimeTypeApplies($mime_type)) {
         return TRUE;
diff --git a/core/modules/file/src/Plugin/rest/resource/FileUploadResource.php b/core/modules/file/src/Plugin/rest/resource/FileUploadResource.php
index b46c692949..00bf152b56 100644
--- a/core/modules/file/src/Plugin/rest/resource/FileUploadResource.php
+++ b/core/modules/file/src/Plugin/rest/resource/FileUploadResource.php
@@ -23,7 +23,6 @@
 use Drupal\rest\RequestHandler;
 use Psr\Log\LoggerInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
-use Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesserInterface;
 use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
 use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;
 use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
@@ -103,7 +102,7 @@ class FileUploadResource extends ResourceBase {
   /**
    * The MIME type guesser.
    *
-   * @var \Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesserInterface
+   * @var \Symfony\Component\Mime\MimeTypeGuesserInterface
    */
   protected $mimeTypeGuesser;
 
@@ -147,7 +146,7 @@ class FileUploadResource extends ResourceBase {
    *   The entity field manager.
    * @param \Drupal\Core\Session\AccountInterface $current_user
    *   The currently authenticated user.
-   * @param \Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesserInterface $mime_type_guesser
+   * @param \Symfony\Component\Mime\MimeTypeGuesserInterface $mime_type_guesser
    *   The MIME type guesser.
    * @param \Drupal\Core\Utility\Token $token
    *   The token replacement instance.
@@ -156,7 +155,7 @@ class FileUploadResource extends ResourceBase {
    * @param \Drupal\Core\Config\Config $system_file_config
    *   The system file configuration.
    */
-  public function __construct(array $configuration, $plugin_id, $plugin_definition, $serializer_formats, LoggerInterface $logger, FileSystemInterface $file_system, EntityTypeManagerInterface $entity_type_manager, EntityFieldManagerInterface $entity_field_manager, AccountInterface $current_user, MimeTypeGuesserInterface $mime_type_guesser, Token $token, LockBackendInterface $lock, Config $system_file_config) {
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, $serializer_formats, LoggerInterface $logger, FileSystemInterface $file_system, EntityTypeManagerInterface $entity_type_manager, EntityFieldManagerInterface $entity_field_manager, AccountInterface $current_user, $mime_type_guesser, Token $token, LockBackendInterface $lock, Config $system_file_config) {
     parent::__construct($configuration, $plugin_id, $plugin_definition, $serializer_formats, $logger);
     $this->fileSystem = $file_system;
     $this->entityTypeManager = $entity_type_manager;
@@ -254,7 +253,7 @@ public function post(Request $request, $entity_type_id, $bundle, $field_name) {
     $file = File::create([]);
     $file->setOwnerId($this->currentUser->id());
     $file->setFilename($prepared_filename);
-    $file->setMimeType($this->mimeTypeGuesser->guess($prepared_filename));
+    $file->setMimeType($this->mimeTypeGuesser->guessMimeType($prepared_filename));
     $file->setFileUri($file_uri);
     // Set the size. This is done in File::preSave() but we validate the file
     // before it is saved.
diff --git a/core/modules/image/src/Plugin/Field/FieldType/ImageItem.php b/core/modules/image/src/Plugin/Field/FieldType/ImageItem.php
index e462dc6f72..69cebbb55c 100644
--- a/core/modules/image/src/Plugin/Field/FieldType/ImageItem.php
+++ b/core/modules/image/src/Plugin/Field/FieldType/ImageItem.php
@@ -351,7 +351,7 @@ public static function generateSampleValue(FieldDefinitionInterface $field_defin
         $image = File::create();
         $image->setFileUri($path);
         $image->setOwnerId(\Drupal::currentUser()->id());
-        $image->setMimeType(\Drupal::service('file.mime_type.guesser')->guess($path));
+        $image->setMimeType(\Drupal::service('file.mime_type.guesser')->guessMimeType($path));
         $image->setFileName($file_system->basename($path));
         $destination_dir = static::doGetUploadLocation($settings);
         $file_system->prepareDirectory($destination_dir, FileSystemInterface::CREATE_DIRECTORY);
diff --git a/core/modules/jsonapi/src/Controller/TemporaryJsonapiFileFieldUploader.php b/core/modules/jsonapi/src/Controller/TemporaryJsonapiFileFieldUploader.php
index 2847e17e53..2589be8ef4 100644
--- a/core/modules/jsonapi/src/Controller/TemporaryJsonapiFileFieldUploader.php
+++ b/core/modules/jsonapi/src/Controller/TemporaryJsonapiFileFieldUploader.php
@@ -21,7 +21,6 @@
 use Drupal\file\Entity\File;
 use Drupal\file\Plugin\Field\FieldType\FileFieldItemList;
 use Psr\Log\LoggerInterface;
-use Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesserInterface;
 use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpKernel\Exception\HttpException;
@@ -73,7 +72,7 @@ class TemporaryJsonapiFileFieldUploader {
   /**
    * The MIME type guesser.
    *
-   * @var \Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesserInterface
+   * @var \Symfony\Mime\MimeTypeGuesserInterface
    */
   protected $mimeTypeGuesser;
 
@@ -105,7 +104,7 @@ class TemporaryJsonapiFileFieldUploader {
    *   A logger instance.
    * @param \Drupal\Core\File\FileSystemInterface $file_system
    *   The file system service.
-   * @param \Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesserInterface $mime_type_guesser
+   * @param \Symfony\Component\Mime\MimeTypeGuesserInterface $mime_type_guesser
    *   The MIME type guesser.
    * @param \Drupal\Core\Utility\Token $token
    *   The token replacement instance.
@@ -114,7 +113,7 @@ class TemporaryJsonapiFileFieldUploader {
    * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
    *   The config factory.
    */
-  public function __construct(LoggerInterface $logger, FileSystemInterface $file_system, MimeTypeGuesserInterface $mime_type_guesser, Token $token, LockBackendInterface $lock, ConfigFactoryInterface $config_factory) {
+  public function __construct(LoggerInterface $logger, FileSystemInterface $file_system, $mime_type_guesser, Token $token, LockBackendInterface $lock, ConfigFactoryInterface $config_factory) {
     $this->logger = $logger;
     $this->fileSystem = $file_system;
     $this->mimeTypeGuesser = $mime_type_guesser;
@@ -173,7 +172,7 @@ public function handleFileUploadForField(FieldDefinitionInterface $field_definit
     $file = File::create([]);
     $file->setOwnerId($owner->id());
     $file->setFilename($prepared_filename);
-    $file->setMimeType($this->mimeTypeGuesser->guess($prepared_filename));
+    $file->setMimeType($this->mimeTypeGuesser->guessMimeType($prepared_filename));
     $file->setFileUri($file_uri);
     // Set the size. This is done in File::preSave() but we validate the file
     // before it is saved.
diff --git a/core/modules/responsive_image/responsive_image.module b/core/modules/responsive_image/responsive_image.module
index 36ea84d2b1..e0d06071b6 100644
--- a/core/modules/responsive_image/responsive_image.module
+++ b/core/modules/responsive_image/responsive_image.module
@@ -477,7 +477,7 @@ function responsive_image_get_mime_type($image_style_name, $extension) {
   else {
     $fake_path = 'responsive_image.' . ImageStyle::load($image_style_name)->getDerivativeExtension($extension);
   }
-  return Drupal::service('file.mime_type.guesser.extension')->guess($fake_path);
+  return Drupal::service('file.mime_type.guesser.extension')->guessMimeType($fake_path);
 }
 
 /**
diff --git a/core/modules/system/src/Form/ThemeSettingsForm.php b/core/modules/system/src/Form/ThemeSettingsForm.php
index 46885f25f7..af6f36a104 100644
--- a/core/modules/system/src/Form/ThemeSettingsForm.php
+++ b/core/modules/system/src/Form/ThemeSettingsForm.php
@@ -10,7 +10,6 @@
 use Drupal\Core\StreamWrapper\PublicStream;
 use Drupal\Core\StreamWrapper\StreamWrapperManager;
 use Symfony\Component\DependencyInjection\ContainerInterface;
-use Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesserInterface;
 use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
 use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
@@ -41,7 +40,7 @@ class ThemeSettingsForm extends ConfigFormBase {
   /**
    * The MIME type guesser.
    *
-   * @var \Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesserInterface
+   * @var \Symfony\Component\Mime\MimeTypeGuesserInterface
    */
   protected $mimeTypeGuesser;
 
@@ -75,14 +74,14 @@ class ThemeSettingsForm extends ConfigFormBase {
    *   The module handler instance to use.
    * @param \Drupal\Core\Extension\ThemeHandlerInterface $theme_handler
    *   The theme handler.
-   * @param \Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesserInterface $mime_type_guesser
+   * @param \Symfony\Component\Mime\MimeTypeGuesserInterface $mime_type_guesser
    *   The MIME type guesser instance to use.
    * @param \Drupal\Core\Theme\ThemeManagerInterface $theme_manager
    *   The theme manager.
    * @param \Drupal\Core\File\FileSystemInterface $file_system
    *   The file system.
    */
-  public function __construct(ConfigFactoryInterface $config_factory, ModuleHandlerInterface $module_handler, ThemeHandlerInterface $theme_handler, MimeTypeGuesserInterface $mime_type_guesser, ThemeManagerInterface $theme_manager, FileSystemInterface $file_system) {
+  public function __construct(ConfigFactoryInterface $config_factory, ModuleHandlerInterface $module_handler, ThemeHandlerInterface $theme_handler, $mime_type_guesser, ThemeManagerInterface $theme_manager, FileSystemInterface $file_system) {
     parent::__construct($config_factory);
 
     $this->moduleHandler = $module_handler;
@@ -494,7 +493,7 @@ public function submitForm(array &$form, FormStateInterface $form_state) {
     }
 
     if (empty($values['default_favicon']) && !empty($values['favicon_path'])) {
-      $values['favicon_mimetype'] = $this->mimeTypeGuesser->guess($values['favicon_path']);
+      $values['favicon_mimetype'] = $this->mimeTypeGuesser->guessMimeType($values['favicon_path']);
     }
 
     theme_settings_convert_to_config($values, $config)->save();