diff -u b/core/modules/media_entity/config/schema/media_entity.schema.yml b/core/modules/media_entity/config/schema/media_entity.schema.yml
--- b/core/modules/media_entity/config/schema/media_entity.schema.yml
+++ b/core/modules/media_entity/config/schema/media_entity.schema.yml
@@ -4,7 +4,7 @@
   mapping:
     icon_base:
       type: string
-      label: 'Base folder for icons installation'
+      label: 'URI where media type icons will be installed'
 
 media_entity.bundle.*:
   type: config_entity
diff -u b/core/modules/media_entity/js/media_bundle_form.js b/core/modules/media_entity/js/media_bundle_form.js
--- b/core/modules/media_entity/js/media_bundle_form.js
+++ b/core/modules/media_entity/js/media_bundle_form.js
@@ -28,12 +28,12 @@
         }
         return vals.join(', ');
       });
-      $('#edit-language', context).drupalSetSummary(function (context) {
+      $(context).find('#edit-language').drupalSetSummary(function (context) {
         var vals = [];
 
-        vals.push($('.js-form-item-language-configuration-langcode select option:selected', context).text());
+        vals.push($(context).find('.js-form-item-language-configuration-langcode select option:selected').text());
 
-        $('input:checked', context).next('label').each(function () {
+        $(context).find('input:checked').next('label').each(function () {
           vals.push(Drupal.checkPlain($(this).text()));
         });
 
diff -u b/core/modules/media_entity/media_entity.api.php b/core/modules/media_entity/media_entity.api.php
--- b/core/modules/media_entity/media_entity.api.php
+++ b/core/modules/media_entity/media_entity.api.php
@@ -16,7 +16,7 @@
  * @param array $types
  *   The array of type plugins, keyed on the machine-readable name.
  */
-function hook_media_entity_type_info_alter(&$types) {
+function hook_media_entity_type_info_alter(array &$types) {
   $types['youtube']['label'] = t('Youtube rocks!');
 }
 
diff -u b/core/modules/media_entity/media_entity.libraries.yml b/core/modules/media_entity/media_entity.libraries.yml
--- b/core/modules/media_entity/media_entity.libraries.yml
+++ b/core/modules/media_entity/media_entity.libraries.yml
@@ -3,8 +3,6 @@
   js:
     'js/media_form.js': {}
   dependencies:
-    - core/jquery
-    - core/drupal
     - core/drupal.form
 
 media_bundle_form:
@@ -14,4 +12,2 @@
   dependencies:
-    - core/jquery
-    - core/drupal
     - core/drupal.form
diff -u b/core/modules/media_entity/media_entity.theme.inc b/core/modules/media_entity/media_entity.theme.inc
--- b/core/modules/media_entity/media_entity.theme.inc
+++ b/core/modules/media_entity/media_entity.theme.inc
@@ -18,7 +18,7 @@
  *   An associative array containing:
  *   - media: An individual media for display.
  */
-function template_preprocess_media(&$variables) {
+function template_preprocess_media(array &$variables) {
   /** @var \Drupal\media_entity\MediaInterface $media */
   $media = $variables['elements']['#media'];
 
diff -u b/core/modules/media_entity/src/Entity/Media.php b/core/modules/media_entity/src/Entity/Media.php
--- b/core/modules/media_entity/src/Entity/Media.php
+++ b/core/modules/media_entity/src/Entity/Media.php
@@ -16,6 +16,8 @@
  * @ContentEntityType(
  *   id = "media",
  *   label = @Translation("Media"),
+ *   label_singular = @Translation("media item"),
+ *   label_plural = @Translation("media items"),
  *   bundle_label = @Translation("Media bundle"),
  *   handlers = {
  *     "storage" = "Drupal\Core\Entity\Sql\SqlContentEntityStorage",
diff -u b/core/modules/media_entity/src/Entity/MediaBundle.php b/core/modules/media_entity/src/Entity/MediaBundle.php
--- b/core/modules/media_entity/src/Entity/MediaBundle.php
+++ b/core/modules/media_entity/src/Entity/MediaBundle.php
@@ -60,35 +60,35 @@
    *
    * @var string
    */
-  public $id;
+  protected $id;
 
   /**
    * The human-readable name of the media bundle.
    *
    * @var string
    */
-  public $label;
+  protected $label;
 
   /**
    * A brief description of this media bundle.
    *
    * @var string
    */
-  public $description;
+  protected $description;
 
   /**
    * The type plugin id.
    *
    * @var string
    */
-  public $type = 'generic';
+  protected $type = 'generic';
 
   /**
    * Are thumbnail downloads queued.
    *
    * @var bool
    */
-  public $queue_thumbnail_downloads = FALSE;
+  protected $queue_thumbnail_downloads = FALSE;
 
   /**
    * Default value of the 'Create new revision' checkbox of this media bundle.
@@ -102,7 +102,7 @@
    *
    * @var array
    */
-  public $type_configuration = [];
+  protected $type_configuration = [];
 
   /**
    * Type lazy plugin collection.
@@ -119,13 +119,6 @@
   public $field_map = [];
 
   /**
-   * Default status of this media bundle.
-   *
-   * @var array
-   */
-  public $status = TRUE;
-
-  /**
    * {@inheritdoc}
    */
   public function getPluginCollections() {
diff -u b/core/modules/media_entity/src/MediaBundleForm.php b/core/modules/media_entity/src/MediaBundleForm.php
--- b/core/modules/media_entity/src/MediaBundleForm.php
+++ b/core/modules/media_entity/src/MediaBundleForm.php
@@ -12,7 +12,7 @@
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
- * Form controller for node type forms.
+ * Form controller for media bundle forms.
  */
 class MediaBundleForm extends EntityForm {
 
@@ -86,7 +86,7 @@
     $form = parent::form($form, $form_state);
 
     /** @var \Drupal\media_entity\MediaBundleInterface $bundle */
-    $form['#entity'] = $bundle = $this->entity;
+    $form['#entity'] = $bundle = $this->getEntity();
     $form_state->set('bundle', $bundle->id());
 
     if ($this->operation == 'add') {
@@ -160,7 +160,7 @@
 
     /** @var \Drupal\media_entity\MediaTypeInterface $plugin */
     if ($plugin = $bundle->getType()) {
-      $plugin_configuration = (empty($this->configurableInstances[$plugin->getPluginId()]['plugin_config'])) ? $bundle->type_configuration : $this->configurableInstances[$plugin->getPluginId()]['plugin_config'];
+      $plugin_configuration = (empty($this->configurableInstances[$plugin->getPluginId()]['plugin_config'])) ? $bundle->getTypeConfiguration() : $this->configurableInstances[$plugin->getPluginId()]['plugin_config'];
       /** @var \Drupal\media_entity\MediaTypeBase $instance */
       $instance = $this->mediaTypeManager->createInstance($plugin->getPluginId(), $plugin_configuration);
       // Store the configuration for validate and submit handlers.
@@ -305,10 +305,8 @@
   public function submitForm(array &$form, FormStateInterface $form_state) {
     parent::submitForm($form, $form_state);
 
-    $workflow_options = ['status', 'queue_thumbnail_downloads'];
-    foreach ($workflow_options as $option) {
-      $this->entity->$option = (bool) $form_state->getValue(['options', $option]);
-    }
+    $this->entity->setQueueThumbnailDownloads((bool) $form_state->getValue(['options', 'queue_thumbnail_downloads']));
+    $this->entity->setStatus((bool) $form_state->getValue(['options', 'status']));
 
     $this->entity->setNewRevision((bool) $form_state->getValue(['options', 'new_revision']));
 
diff -u b/core/modules/media_entity/src/MediaForm.php b/core/modules/media_entity/src/MediaForm.php
--- b/core/modules/media_entity/src/MediaForm.php
+++ b/core/modules/media_entity/src/MediaForm.php
@@ -31,7 +31,7 @@
     parent::prepareEntity();
 
     // Set up default values, if required.
-    if (!$this->entity->isNew()) {
+    if (!$this->getEntity()->isNew()) {
       $this->entity->setRevisionLogMessage(NULL);
       $this->entity->setOwnerId($this->currentUser()->id());
       $this->entity->setCreatedTime(\Drupal::time()->getRequestTime());
@@ -43,7 +43,7 @@
    */
   public function form(array $form, FormStateInterface $form_state) {
     $form = parent::form($form, $form_state);
-    $entity_type = $this->entity->getEntityType();
+    $entity_type = $this->getEntity()->getEntityType();
     /** @var \Drupal\media_entity\Entity\MediaBundle $bundle_entity */
     $bundle_entity = $this->entity->bundle->entity;
     $account = $this->currentUser();
diff -u b/core/modules/media_entity/tests/src/Functional/MediaUiFunctionalTest.php b/core/modules/media_entity/tests/src/Functional/MediaUiFunctionalTest.php
--- b/core/modules/media_entity/tests/src/Functional/MediaUiFunctionalTest.php
+++ b/core/modules/media_entity/tests/src/Functional/MediaUiFunctionalTest.php
@@ -82,7 +82,7 @@
     // Test that there is no empty vertical tabs element, if the container is
     // empty (see #2750697).
     // Make the "Publisher ID" and "Created" fields hidden.
-    $this->drupalGet('/admin/structure/media/manage/' . $bundle->id . '/form-display');
+    $this->drupalGet('/admin/structure/media/manage/' . $bundle->id() . '/form-display');
     $page->selectFieldOption('fields[created][parent]', 'hidden');
     $page->selectFieldOption('fields[uid][parent]', 'hidden');
     $page->pressButton('Save');
@@ -140,10 +140,10 @@
 
     // Checks for the first media bundle.
     $assert_session->pageTextContains($first_media_bundle->label());
-    $assert_session->pageTextContains($first_media_bundle->description);
+    $assert_session->pageTextContains($first_media_bundle->getDescription());
     // Checks for the second media bundle.
     $assert_session->pageTextContains($second_media_bundle->label());
-    $assert_session->pageTextContains($second_media_bundle->description);
+    $assert_session->pageTextContains($second_media_bundle->getDescription());
 
     // Continue testing media bundle filter.
     $first_media_item = Media::create(['bundle' => $first_media_bundle->id()]);
diff -u b/core/modules/media_entity/tests/src/FunctionalJavascript/MediaUiJavascriptTest.php b/core/modules/media_entity/tests/src/FunctionalJavascript/MediaUiJavascriptTest.php
--- b/core/modules/media_entity/tests/src/FunctionalJavascript/MediaUiJavascriptTest.php
+++ b/core/modules/media_entity/tests/src/FunctionalJavascript/MediaUiJavascriptTest.php
@@ -138,7 +138,7 @@
     $this->assertTrue($loaded_bundle->shouldCreateNewRevision());
     $this->assertTrue($loaded_bundle->getQueueThumbnailDownloads());
     $this->assertFalse($loaded_bundle->getStatus());
-    $this->assertEquals($loaded_bundle->field_map, ['field_1' => 'name']);
+    $this->assertEquals($loaded_bundle->getFieldMap(), ['field_1' => 'name']);
 
     // Test that a media being created with default status to "FALSE" will be
     // created unpublished.