diff --git a/core/includes/module.inc b/core/includes/module.inc
index 6b03302..a37c654 100644
--- a/core/includes/module.inc
+++ b/core/includes/module.inc
@@ -23,9 +23,7 @@
  * @see \Drupal\Core\Extension\ThemeHandler::listInfo()
  */
 function system_list($type) {
-  return array_filter(\Drupal::service('extension.list.' . $type)->getList(), function (Extension $extension) {
-    return $extension->status;
-  });
+  return \Drupal::service('extension.list.' . $type)->getInstalled();
 }
 
 /**
diff --git a/core/lib/Drupal/Core/Extension/ExtensionList.php b/core/lib/Drupal/Core/Extension/ExtensionList.php
index 218c9bf..5606404 100644
--- a/core/lib/Drupal/Core/Extension/ExtensionList.php
+++ b/core/lib/Drupal/Core/Extension/ExtensionList.php
@@ -263,6 +263,26 @@ public function get($extension_name) {
   }
 
   /**
+   * Returns a list of installed extensions.
+   *
+   * @return \Drupal\Core\Extension\Extension[]
+   *   A list of installed extension objects, keyed by machine name.
+   */
+  public function getInstalled() {
+    return array_intersect_key($this->getList(), array_flip($this->getInstalledExtensionNames()));
+  }
+
+  /**
+   * Returns a list of uninstalled extensions.
+   *
+   * @return \Drupal\Core\Extension\Extension[]
+   *   A list of uninstalled extension objects, keyed by machine name.
+   */
+  public function getUninstalled() {
+    return array_diff_key($this->getList(), array_flip($this->getInstalledExtensionNames()));
+  }
+
+  /**
    * Returns all available extensions.
    *
    * @return \Drupal\Core\Extension\Extension[]
diff --git a/core/lib/Drupal/Core/Extension/ThemeHandler.php b/core/lib/Drupal/Core/Extension/ThemeHandler.php
index a608b86..7230163 100644
--- a/core/lib/Drupal/Core/Extension/ThemeHandler.php
+++ b/core/lib/Drupal/Core/Extension/ThemeHandler.php
@@ -164,12 +164,7 @@ public function uninstall(array $theme_list) {
   public function listInfo() {
     if (!isset($this->list)) {
       $this->list = [];
-      $themes = $this->getThemeExtensionList()->getList();
-      foreach ($themes as $theme) {
-        if ($theme->status) {
-          $this->addTheme($theme);
-        }
-      }
+      array_map([$this, 'addTheme'], $this->getThemeExtensionList()->getInstalled());
     }
     return $this->list;
   }
diff --git a/core/tests/Drupal/Tests/Core/Extension/ExtensionListTest.php b/core/tests/Drupal/Tests/Core/Extension/ExtensionListTest.php
index 80a0c76..33d634a 100644
--- a/core/tests/Drupal/Tests/Core/Extension/ExtensionListTest.php
+++ b/core/tests/Drupal/Tests/Core/Extension/ExtensionListTest.php
@@ -206,6 +206,36 @@ public function testReset() {
   }
 
   /**
+   * @covers ::getInstalled
+   * @covers ::getUninstalled
+   */
+  public function testInstalledUninstalled() {
+    $test_extension_list = $this->setupTestExtensionList(['test_name_1', 'test_name_2', 'test_name_3']);
+    $all = $test_extension_list->getList();
+    $installed = $test_extension_list->getInstalled();
+    $uninstalled = $test_extension_list->getUninstalled();
+
+    $this->assertCount(3, $all);
+    $this->assertCount(0, $installed);
+    $this->assertCount(3, $uninstalled);
+    $this->assertEquals(['test_name_1', 'test_name_2', 'test_name_3'], array_keys($all));
+    $this->assertEquals(['test_name_1', 'test_name_2', 'test_name_3'], array_keys($uninstalled));
+
+    $test_extension_list->setInstalledExtensions(['test_name_1', 'test_name_2']);
+    $test_extension_list->reset();
+    $all = $test_extension_list->getList();
+    $installed = $test_extension_list->getInstalled();
+    $uninstalled = $test_extension_list->getUninstalled();
+
+    $this->assertCount(3, $all);
+    $this->assertCount(2, $installed);
+    $this->assertCount(1, $uninstalled);
+    $this->assertEquals(['test_name_1', 'test_name_2', 'test_name_3'], array_keys($all));
+    $this->assertEquals(['test_name_1', 'test_name_2'], array_keys($installed));
+    $this->assertEquals(['test_name_3'], array_keys($uninstalled));
+  }
+
+  /**
    * @return \Drupal\Tests\Core\Extension\TestExtension
    */
   protected function setupTestExtensionList($extension_names = ['test_name']) {