diff --git a/core/lib/Drupal/Core/Batch/Batch.php b/core/lib/Drupal/Core/Batch/Batch.php
index 03ee311..32a5ff0 100644
--- a/core/lib/Drupal/Core/Batch/Batch.php
+++ b/core/lib/Drupal/Core/Batch/Batch.php
@@ -75,11 +75,11 @@ class Batch {
   protected $file;
 
   /**
-   * An array of CSS file to be included when processing the batch.
+   * An array of libraries to be included when processing the batch.
    *
-   * @var array
+   * @var string[]
    */
-  protected $css = [];
+  protected $libraries = [];
 
   /**
    * An array of options to be used with the redirect URL.
@@ -182,13 +182,8 @@ public static function createFromArray(array $batch_definition) {
       $new_batch->setFile($batch_definition['file']);
     }
 
-    if (isset($batch_definition['css'])) {
-      if (is_array($batch_definition['css'])) {
-        $new_batch->setCss($batch_definition['css']);
-      }
-      else {
-        $new_batch->addCss($batch_definition['css']);
-      }
+    if (isset($batch_definition['library'])) {
+      $new_batch->addLibraries($batch_definition['library']);
     }
 
     if (isset($batch_definition['url_options'])) {
@@ -298,18 +293,19 @@ public function setFile($filename) {
   }
 
   /**
-   * Sets the location of CSS files.
+   * Sets the libraries to use when processing the batch.
    *
-   * Adds the CSS files for use on the progress page. Any previously added CSS
-   * files are removed. Use \Drupal\Core\Batch\Batch::addCss() to add a file.
+   * Adds the libraries for use on the progress page. Any previously added
+   * libraries are removed. Use \Drupal\Core\Batch\Batch::addLibraries() to add
+   * one or more libraries.
    *
-   * @param string[] $filenames
-   *   The CSS files to be used.
+   * @param string[] $libraries
+   *   The libraries to be used.
    *
    * @return $this
    */
-  public function setCss(array $filenames) {
-    $this->css = $filenames;
+  public function setLibraries(array $libraries) {
+    $this->libraries = $libraries;
     return $this;
   }
 
@@ -387,15 +383,18 @@ public function addOperation($callback, array $arguments = []) {
   }
 
   /**
-   * Adds a CSS file to be used on the process page.
+   * Adds libraries to be used on the process page.
    *
-   * @param string $filename
-   *   The CSS file to use.
+   * @param string|string[] $libraries
+   *   The libraries to add.
    *
    * @return $this
    */
-  public function addCss($filename) {
-    $this->css[] = $filename;
+  public function addLibraries($libraries) {
+    if (!is_array($libraries)) {
+      $libraries = [$libraries];
+    }
+    $this->libraries = $this->libraries + $libraries;
     return $this;
   }
 
@@ -429,7 +428,7 @@ public function toArray() {
       'error_message' => $this->errorMessage ?: '',
       'finished' => $this->finished,
       'file' => $this->file,
-      'css' => $this->css ?: [],
+      'library' => $this->libraries ?: [],
       'url_options' => $this->urlOptions ?: [],
       'progressive' => $this->progressive,
       'queue' => $this->queue ?: NULL,