diff --git a/core/modules/file/src/FileUploader.php b/core/modules/file/src/FileUploader.php
index cf344aff15..0d49240518 100644
--- a/core/modules/file/src/FileUploader.php
+++ b/core/modules/file/src/FileUploader.php
@@ -26,13 +26,13 @@
 /**
  * Reads data from an upload stream and creates a corresponding file entity.
  *
- * This is implemented at the field-level for the following reasons:
+ * This is implemented at the field level for the following reasons:
  *   - Validation for uploaded files is tied to fields (allowed extensions, max
  *     size, etc..).
  *   - The actual files do not need to be stored in another temporary location,
  *     to be later moved when they are referenced from a file field.
- *   - Permission to upload a file can be determined by a user's field and
- *     entity level access.
+ *   - Permission to upload a file can be determined by a user's field- and
+ *     entity-level access.
  */
 class FileUploader implements FileUploaderInterface {
 
@@ -145,7 +145,7 @@ public function handleFileUploadForField(FieldDefinitionInterface $field_definit
     $lock_id = $this->generateLockIdFromFileUri($file_uri);
 
     if (!$this->lock->acquire($lock_id)) {
-      throw new HttpException(503, sprintf('File "%s" is already locked for writing'), NULL, ['Retry-After' => 1]);
+      throw new HttpException(503, sprintf('File "%s" is already locked for writing.'), NULL, ['Retry-After' => 1]);
     }
 
     // Begin building file entity.
@@ -169,7 +169,7 @@ public function handleFileUploadForField(FieldDefinitionInterface $field_definit
     // FILE_EXISTS_ERROR as the file location has already been determined above
     // in file_unmanaged_prepare().
     if (!file_unmanaged_move($temp_file_path, $file_uri, FILE_EXISTS_ERROR)) {
-      throw new HttpException(500, 'Temporary file could not be moved to file location');
+      throw new HttpException(500, 'Temporary file could not be moved to file location.');
     }
 
     $file->save();
@@ -192,9 +192,9 @@ public function handleFileUploadForField(FieldDefinitionInterface $field_definit
    *   Thrown when the 'Content-Disposition' request header is invalid.
    */
   public static function validateAndParseContentDispositionHeader(Request $request) {
-    // Firstly, check the header exists.
+    // First, check the header exists.
     if (!$request->headers->has('content-disposition')) {
-      throw new BadRequestHttpException('"Content-Disposition" header is required. A file name in the format "filename=FILENAME" must be provided');
+      throw new BadRequestHttpException('"Content-Disposition" header is required. A file name in the format "filename=FILENAME" must be provided.');
     }
 
     $content_disposition = $request->headers->get('content-disposition');
@@ -203,12 +203,12 @@ public static function validateAndParseContentDispositionHeader(Request $request
     // i.e. 'filename=""'. This also matches on a word boundary so other keys
     // like 'not_a_filename' don't work.
     if (!preg_match(static::REQUEST_HEADER_FILENAME_REGEX, $content_disposition, $matches)) {
-      throw new BadRequestHttpException('No filename found in "Content-Disposition" header. A file name in the format "filename=FILENAME" must be provided');
+      throw new BadRequestHttpException('No filename found in "Content-Disposition" header. A file name in the format "filename=FILENAME" must be provided.');
     }
 
     // Check for the "filename*" format. This is currently unsupported.
     if (!empty($matches['star'])) {
-      throw new BadRequestHttpException('The extended "filename*" format is currently not supported in the "Content-Disposition" header');
+      throw new BadRequestHttpException('The extended "filename*" format is currently not supported in the "Content-Disposition" header.');
     }
 
     // Don't validate the actual filename here, that will be done by the upload
@@ -286,14 +286,14 @@ protected function readStreamDataToFile($stream) {
           // Close the file streams.
           fclose($temp_file);
           $this->logger->error('Input data could not be read');
-          throw new HttpException(500, 'Input file data could not be read');
+          throw new HttpException(500, 'Input file data could not be read.');
         }
 
         if (fwrite($temp_file, $read) === FALSE) {
           // Close the file streams.
           fclose($temp_file);
           $this->logger->error('Temporary file data for "%path" could not be written', ['%path' => $temp_file_path]);
-          throw new HttpException(500, 'Temporary file data could not be written');
+          throw new HttpException(500, 'Temporary file data could not be written.');
         }
       }
 
@@ -303,7 +303,7 @@ protected function readStreamDataToFile($stream) {
     else {
       // Close the file streams.
       fclose($temp_file);
-      $this->logger->error('Temporary file "%path" could not be opened for file upload', ['%path' => $temp_file_path]);
+      $this->logger->error('Temporary file "%path" could not be opened for file upload.', ['%path' => $temp_file_path]);
       throw new HttpException(500, 'Temporary file could not be opened');
     }
 
diff --git a/core/modules/file/src/FileUploaderInterface.php b/core/modules/file/src/FileUploaderInterface.php
index 399fcbabcf..88f4de7ea7 100644
--- a/core/modules/file/src/FileUploaderInterface.php
+++ b/core/modules/file/src/FileUploaderInterface.php
@@ -8,12 +8,12 @@
 /**
  * Interface to handle binary file data uploads and file entity creation.
  *
- * This is implemented at the field-level for the following reasons:
+ * This is implemented at the field level for the following reasons:
  *   - Validation for uploaded files is tied to fields (allowed extensions, max
  *     size, etc..).
  *   - The actual files do not need to be stored in another temporary location,
  *     to be later moved when they are referenced from a file field.
- *   - Permission to upload a file can be determined by a users field level
+ *   - Permission to upload a file can be determined by a user's field-level
  *     create access to the file field.
  */
 interface FileUploaderInterface {
@@ -28,8 +28,8 @@
    * @param resource $stream
    *   The upload stream.
    * @param \Drupal\Core\Session\AccountInterface $owner
-   *   The owner of the file. Defaults to the current user. Note, it is the
-   *   responsibility of the caller to enforce access.
+   *   The owner of the file. Note, it is the responsibility of the caller to
+   *   enforce access.
    *
    * @return \Drupal\file\FileInterface|\Drupal\Core\Entity\EntityConstraintViolationListInterface
    *   The newly uploaded file entity, or a list of validation constraint