reverted:
--- b/core/modules/menu_link_content/tests/src/Kernel/Plugin/migrate/source/d6/MenuLinkSourceTranslationTest.php
+++ /dev/null
@@ -1,256 +0,0 @@
-<?php
-
-namespace Drupal\Tests\menu_link_content\Kernel\Plugin\migrate\source\d6;
-
-use Drupal\Tests\migrate\Kernel\MigrateSqlSourceTestBase;
-
-/**
- * Tests menu link translation source plugin.
- *
- * @covers \Drupal\menu_link_content\Plugin\migrate\source\d6\MenuLinkTranslation
- * @group menu_link_content
- */
-class MenuLinkSourceTranslationTest extends MigrateSqlSourceTestBase {
-
-  /**
-   * {@inheritdoc}
-   */
-  public static $modules = ['menu_link_content', 'migrate_drupal'];
-
-  /**
-   * {@inheritdoc}
-   */
-  public function providerSource() {
-    $test = [];
-    $test[0]['source_data']['menu_links'] = [
-      [
-        'menu_name' => 'menu-test-menu',
-        'mlid' => 138,
-        'plid' => 0,
-        'link_path' => 'admin',
-        'router_path' => 'admin',
-        'link_title' => 'Test 1',
-        'options' => 'a:1:{s:10:"attributes";a:1:{s:5:"title";s:16:"Test menu link 1";}}',
-        'module' => 'menu',
-        'hidden' => 0,
-        'external' => 0,
-        'has_children' => 1,
-        'expanded' => 0,
-        'weight' => 15,
-        'depth' => 1,
-        'customized' => 1,
-        'p1' => '138',
-        'p2' => '0',
-        'p3' => '0',
-        'p4' => '0',
-        'p5' => '0',
-        'p6' => '0',
-        'p7' => '0',
-        'p8' => '0',
-        'p9' => '0',
-        'updated' => '0',
-        'description' => 'Test menu link 1',
-      ],
-      [
-        'menu_name' => 'menu-test-menu',
-        'mlid' => 139,
-        'plid' => 138,
-        'link_path' => 'admin/modules',
-        'router_path' => 'admin/modules',
-        'link_title' => 'Test 2',
-        'options' => 'a:1:{s:10:"attributes";a:1:{s:5:"title";s:16:"Test menu link 2";}}',
-        'module' => 'menu',
-        'hidden' => 0,
-        'external' => 0,
-        'has_children' => 0,
-        'expanded' => 0,
-        'weight' => 12,
-        'depth' => 2,
-        'customized' => 1,
-        'p1' => '138',
-        'p2' => '139',
-        'p3' => '0',
-        'p4' => '0',
-        'p5' => '0',
-        'p6' => '0',
-        'p7' => '0',
-        'p8' => '0',
-        'p9' => '0',
-        'updated' => '0',
-        'description' => 'Test menu link 2',
-      ],
-      [
-        'menu_name' => 'menu-test-menu',
-        'mlid' => 140,
-        'plid' => 0,
-        'link_path' => 'https://www.drupal.org',
-        'router_path' => 'admin/modules',
-        'link_title' => 'Test 2',
-        'options' => 'a:1:{s:10:"attributes";a:1:{s:5:"title";s:16:"Test menu link 2";}}',
-        'module' => 'menu',
-        'hidden' => 0,
-        'external' => 0,
-        'has_children' => 0,
-        'expanded' => 0,
-        'weight' => 12,
-        'depth' => 2,
-        'customized' => 1,
-        'p1' => '0',
-        'p2' => '0',
-        'p3' => '0',
-        'p4' => '0',
-        'p5' => '0',
-        'p6' => '0',
-        'p7' => '0',
-        'p8' => '0',
-        'p9' => '0',
-        'updated' => '0',
-        'description' => 'Test menu link 2',
-      ],
-      [
-        'menu_name' => 'menu-test-menu',
-        'mlid' => 141,
-        'plid' => 0,
-        'link_path' => 'https://api.drupal.org/api/drupal/8.3.x',
-        'router_path' => 'admin/modules',
-        'link_title' => 'Test 3',
-        'options' => 'a:1:{s:10:"attributes";a:1:{s:5:"title";s:16:"Test menu link 3";}}',
-        'module' => 'menu',
-        'hidden' => 0,
-        'external' => 0,
-        'has_children' => 0,
-        'expanded' => 0,
-        'weight' => 12,
-        'depth' => 2,
-        'customized' => 1,
-        'p1' => '0',
-        'p2' => '0',
-        'p3' => '0',
-        'p4' => '0',
-        'p5' => '0',
-        'p6' => '0',
-        'p7' => '0',
-        'p8' => '0',
-        'p9' => '0',
-        'updated' => '0',
-        'description' => 'Test menu link 3',
-      ],
-    ];
-    $test[0]['source_data']['i18n_strings'] = [
-      [
-        'lid' => 1,
-        'objectid' => 139,
-        'type' => 'item',
-        'property' => 'title',
-        'objectindex' => 0,
-        'format' => 0,
-      ],
-      [
-        'lid' => 2,
-        'objectid' => 139,
-        'type' => 'item',
-        'property' => 'description',
-        'objectindex' => 0,
-        'format' => 0,
-      ],
-      [
-        'lid' => 3,
-        'objectid' => 140,
-        'type' => 'item',
-        'property' => 'description',
-        'objectindex' => 0,
-        'format' => 0,
-      ],
-      [
-        'lid' => 4,
-        'objectid' => 141,
-        'type' => 'item',
-        'property' => 'title',
-        'objectindex' => 0,
-        'format' => 0,
-      ],
-    ];
-    $test[0]['source_data']['locales_target'] = [
-      [
-        'lid' => 1,
-        'language' => 'fr',
-        'translation' => 'fr - title translation',
-        'plid' => 0,
-        'plural' => 0,
-        'u18n_status' => 0,
-      ],
-      [
-        'lid' => 2,
-        'language' => 'fr',
-        'translation' => 'fr - description translation',
-        'plid' => 0,
-        'plural' => 0,
-        'u18n_status' => 0,
-      ],
-      [
-        'lid' => 3,
-        'language' => 'zu',
-        'translation' => 'zu - description translation',
-        'plid' => 0,
-        'plural' => 0,
-        'u18n_status' => 0,
-      ],
-      [
-        'lid' => 4,
-        'language' => 'zu',
-        'translation' => 'zu - title translation',
-        'plid' => 0,
-        'plural' => 0,
-        'u18n_status' => 0,
-      ],
-    ];
-
-    $test[0]['expected_results'] = [
-      [
-        'menu_name' => 'menu-test-menu',
-        'mlid' => 139,
-        'property' => 'title',
-        'language' => 'fr',
-        'title_untranslated' => 'Test 2',
-        'description_untranslated' => 'Test menu link 2',
-        'title_translated' => 'fr - title translation',
-        'description_translated' => 'fr - description translation',
-
-      ],
-      [
-        'menu_name' => 'menu-test-menu',
-        'mlid' => 139,
-        'property' => 'description',
-        'language' => 'fr',
-        'title_untranslated' => 'Test 2',
-        'description_untranslated' => 'Test menu link 2',
-        'title_translated' => 'fr - title translation',
-        'description_translated' => 'fr - description translation',
-      ],
-      [
-        'menu_name' => 'menu-test-menu',
-        'mlid' => 140,
-        'description' => 'Test menu link 2',
-        'property' => 'description',
-        'language' => 'zu',
-        'title_untranslated' => 'Test 2',
-        'description_untranslated' => 'Test menu link 2',
-        'title_translated' => NULL,
-        'description_translated' => 'zu - description translation',
-      ],
-      [
-        'menu_name' => 'menu-test-menu',
-        'mlid' => 141,
-        'property' => 'title',
-        'language' => 'zu',
-        'title_untranslated' => 'Test 3',
-        'description_untranslated' => 'Test menu link 3',
-        'title_translated' => 'zu - title translation',
-        'description_translated' => NULL,
-      ],
-    ];
-
-    return $test;
-  }
-
-}
diff -u b/core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeForm.php b/core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeForm.php
--- b/core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeForm.php
+++ b/core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeForm.php
@@ -322,6 +322,10 @@
       'source_module' => 'i18n',
       'destination_module' => 'menu_link_content',
     ],
+    'd6_language_content_menu_settings' => [
+      'source_module' => 'i18n',
+      'destination_module' => 'menu_link_content',
+    ],
     'menu_settings' => [
       'source_module' => 'menu',
       'destination_module' => 'menu_ui',
only in patch2:
unchanged:
--- /dev/null
+++ b/core/modules/language/migration_templates/d6_language_content_menu_settings.yml
@@ -0,0 +1,17 @@
+id: d6_language_content_menu_settings
+label: Drupal 6 language content settings
+migration_tags:
+  - Drupal 6
+source:
+  plugin: d6_language_content_menu_settings
+  constants:
+    target_type: 'menu_link_content'
+    langcode: 'site_default'
+process:
+  target_bundle: 'constants/target_type'
+  target_entity_type_id: 'constants/target_type'
+  default_langcode: 'constants/site_default'
+  language_alterable: language_alterable
+  third_party_settings/content_translation/enabled: enabled
+destination:
+  plugin: entity:language_content_settings
only in patch2:
unchanged:
--- /dev/null
+++ b/core/modules/language/src/Plugin/migrate/source/d6/LanguageContentMenuSettings.php
@@ -0,0 +1,59 @@
+<?php
+
+namespace Drupal\language\Plugin\migrate\source\d6;
+
+use Drupal\migrate\Row;
+use Drupal\migrate_drupal\Plugin\migrate\source\DrupalSqlBase;
+
+/**
+ * Drupal multilingual menu settings.
+ *
+ * The translation of menu links is enabled if the i18n_menu module is
+ * enabled on the source site and not by a variable.
+ *
+ * @MigrateSource(
+ *   id = "d6_language_content_menu_settings",
+ * )
+ */
+class LanguageContentMenuSettings extends DrupalSqlBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function query() {
+    $query = $this->select('system', 's')
+      ->fields('s', ['name', 'type', 'status'])
+      ->condition('name', 'i18nmenu')
+      ->condition('type', 'module');
+    return $query;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function fields() {
+    $fields = [
+      'name' => $this->t('Name'),
+    ];
+    return $fields;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function prepareRow(Row $row) {
+    $value = empty($row->getSourceProperty('status')) ? FALSE : TRUE;
+    $row->setSourceProperty('language_alterable', $value);
+    $row->setSourceProperty('enabled', $value);
+    return parent::prepareRow($row);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getIds() {
+    $ids['name']['type'] = 'string';
+    return $ids;
+  }
+
+}
only in patch2:
unchanged:
--- /dev/null
+++ b/core/modules/language/tests/src/Kernel/Migrate/d6/MigrateLanguageContentMenuSettingsTest.php
@@ -0,0 +1,50 @@
+<?php
+
+namespace Drupal\Tests\language\Kernel\Migrate\d6;
+
+use Drupal\language\Entity\ConfigurableLanguage;
+use Drupal\language\Entity\ContentLanguageSettings;
+use Drupal\Tests\migrate_drupal\Kernel\d6\MigrateDrupal6TestBase;
+
+/**
+ * Tests migration of the ability to translate menu content.
+ *
+ * @group migrate_drupal_6
+ */
+class MigrateLanguageContentMenuSettingsTest extends MigrateDrupal6TestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = [
+    'language',
+    'content_translation',
+    'menu_link_content',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+    // Create some languages.
+    ConfigurableLanguage::createFromLangcode('en')->save();
+    ConfigurableLanguage::createFromLangcode('fr')->save();
+    $this->executeMigrations(['d6_language_content_menu_settings']);
+  }
+
+  /**
+   * Tests migration of menu translation ability.
+   */
+  public function testLanguageMenuContent() {
+    $config = ContentLanguageSettings::load('menu_link_content.menu_link_content');
+    $this->assertTrue($config instanceof ContentLanguageSettings);
+
+    $this->assertSame('menu_link_content', $config->getTargetEntityTypeId());
+    $this->assertSame('menu_link_content', $config->getTargetBundle());
+    $this->assertSame('site_default', $config->getDefaultLangcode());
+    $this->assertTrue($config->getThirdPartySetting('content_translation', 'enabled'));
+    $this->assertTrue($config->isLanguageAlterable());
+  }
+
+}
only in patch2:
unchanged:
--- /dev/null
+++ b/core/modules/language/tests/src/Kernel/Plugin/migrate/source/d6/LanguageContentMenuSettingsTest.php
@@ -0,0 +1,65 @@
+<?php
+
+namespace Drupal\Tests\language\Kernel\Plugin\migrate\source\d6;
+
+use Drupal\Tests\migrate\Kernel\MigrateSqlSourceTestBase;
+
+/**
+ * Tests menu link translation source plugin.
+ *
+ * @covers \Drupal\language\Plugin\migrate\source\d6\LanguageContentMenuSettings
+ * @group menu_link_content
+ */
+class LanguageContentMenuSettingsTest extends MigrateSqlSourceTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = ['language', 'migrate_drupal'];
+
+  /**
+   * {@inheritdoc}
+   */
+  public function providerSource() {
+    $test = [];
+
+    $test[0]['source_data']['system'] = [
+      [
+        'filename' => 'sites/all/modules/i18n/i18nmenu/i18nmenu.module',
+        'name' => 'i18nmenu',
+        'type' => 'module',
+        'owner' => '',
+        'status' => '1',
+        'throttle' => '0',
+        'bootstrap' => '0',
+        'schema_version' => '0',
+        'weight' => '0',
+        'info' => 'a:10:{s:4:"name";s:16:"Menu translation";s:11:"description";s:40:"Supports translatable custom menu items.";s:12:"dependencies";a:4:{i:0;s:4:"i18n";i:1;s:4:"menu";i:2;s:10:"i18nblocks";i:3;s:11:"i18nstrings";}s:7:"package";s:13:"Multilanguage";s:4:"core";s:3:"6.x";s:7:"version";s:8:"6.x-1.10";s:7:"project";s:4:"i18n";s:9:"datestamp";s:10:"1318336004";s:10:"dependents";a:0:{}s:3:"php";s:5:"4.3.5";},',
+      ],
+      [
+        'filename' => 'sites/all/modules/variable/variable.module ',
+        'name' => 'variable',
+        'type' => 'module',
+        'owner' => '',
+        'status' => '1',
+        'throttle' => '0',
+        'bootstrap' => '0',
+        'schema_version' => '-1',
+        'weight' => '0',
+        'info' => 'a:9:{s:4:"name";s:12:"Variable API";s:11:"description";s:12:"Variable API";s:4:"core";s:3:"6.x";s:7:"version";s:14:"6.x-1.0-alpha1";s:7:"project";s:8:"variable";s:9:"datestamp";s:10:"1414059742";s:12:"dependencies";a:0:{}s:10:"dependents";a:0:{}s:3:"php";s:5:"4.3.5";}',
+      ],
+    ];
+
+    $test[0]['expected_results'] = [
+      [
+        'name' => 'i18nmenu',
+        'status' => '1',
+        'language_alterable' => TRUE,
+        'enabled' => TRUE,
+      ],
+    ];
+
+    return $test;
+  }
+
+}
only in patch2:
unchanged:
--- /dev/null
+++ b/core/modules/menu_link_content/tests/src/Kernel/Plugin/migrate/source/d6/MenuLinkTranslationTest.php
@@ -0,0 +1,256 @@
+<?php
+
+namespace Drupal\Tests\menu_link_content\Kernel\Plugin\migrate\source\d6;
+
+use Drupal\Tests\migrate\Kernel\MigrateSqlSourceTestBase;
+
+/**
+ * Tests menu link translation source plugin.
+ *
+ * @covers \Drupal\menu_link_content\Plugin\migrate\source\d6\MenuLinkTranslation
+ * @group menu_link_content
+ */
+class MenuLinkSourceTranslationTest extends MigrateSqlSourceTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = ['menu_link_content', 'migrate_drupal'];
+
+  /**
+   * {@inheritdoc}
+   */
+  public function providerSource() {
+    $test = [];
+    $test[0]['source_data']['menu_links'] = [
+      [
+        'menu_name' => 'menu-test-menu',
+        'mlid' => 138,
+        'plid' => 0,
+        'link_path' => 'admin',
+        'router_path' => 'admin',
+        'link_title' => 'Test 1',
+        'options' => 'a:1:{s:10:"attributes";a:1:{s:5:"title";s:16:"Test menu link 1";}}',
+        'module' => 'menu',
+        'hidden' => 0,
+        'external' => 0,
+        'has_children' => 1,
+        'expanded' => 0,
+        'weight' => 15,
+        'depth' => 1,
+        'customized' => 1,
+        'p1' => '138',
+        'p2' => '0',
+        'p3' => '0',
+        'p4' => '0',
+        'p5' => '0',
+        'p6' => '0',
+        'p7' => '0',
+        'p8' => '0',
+        'p9' => '0',
+        'updated' => '0',
+        'description' => 'Test menu link 1',
+      ],
+      [
+        'menu_name' => 'menu-test-menu',
+        'mlid' => 139,
+        'plid' => 138,
+        'link_path' => 'admin/modules',
+        'router_path' => 'admin/modules',
+        'link_title' => 'Test 2',
+        'options' => 'a:1:{s:10:"attributes";a:1:{s:5:"title";s:16:"Test menu link 2";}}',
+        'module' => 'menu',
+        'hidden' => 0,
+        'external' => 0,
+        'has_children' => 0,
+        'expanded' => 0,
+        'weight' => 12,
+        'depth' => 2,
+        'customized' => 1,
+        'p1' => '138',
+        'p2' => '139',
+        'p3' => '0',
+        'p4' => '0',
+        'p5' => '0',
+        'p6' => '0',
+        'p7' => '0',
+        'p8' => '0',
+        'p9' => '0',
+        'updated' => '0',
+        'description' => 'Test menu link 2',
+      ],
+      [
+        'menu_name' => 'menu-test-menu',
+        'mlid' => 140,
+        'plid' => 0,
+        'link_path' => 'https://www.drupal.org',
+        'router_path' => 'admin/modules',
+        'link_title' => 'Test 2',
+        'options' => 'a:1:{s:10:"attributes";a:1:{s:5:"title";s:16:"Test menu link 2";}}',
+        'module' => 'menu',
+        'hidden' => 0,
+        'external' => 0,
+        'has_children' => 0,
+        'expanded' => 0,
+        'weight' => 12,
+        'depth' => 2,
+        'customized' => 1,
+        'p1' => '0',
+        'p2' => '0',
+        'p3' => '0',
+        'p4' => '0',
+        'p5' => '0',
+        'p6' => '0',
+        'p7' => '0',
+        'p8' => '0',
+        'p9' => '0',
+        'updated' => '0',
+        'description' => 'Test menu link 2',
+      ],
+      [
+        'menu_name' => 'menu-test-menu',
+        'mlid' => 141,
+        'plid' => 0,
+        'link_path' => 'https://api.drupal.org/api/drupal/8.3.x',
+        'router_path' => 'admin/modules',
+        'link_title' => 'Test 3',
+        'options' => 'a:1:{s:10:"attributes";a:1:{s:5:"title";s:16:"Test menu link 3";}}',
+        'module' => 'menu',
+        'hidden' => 0,
+        'external' => 0,
+        'has_children' => 0,
+        'expanded' => 0,
+        'weight' => 12,
+        'depth' => 2,
+        'customized' => 1,
+        'p1' => '0',
+        'p2' => '0',
+        'p3' => '0',
+        'p4' => '0',
+        'p5' => '0',
+        'p6' => '0',
+        'p7' => '0',
+        'p8' => '0',
+        'p9' => '0',
+        'updated' => '0',
+        'description' => 'Test menu link 3',
+      ],
+    ];
+    $test[0]['source_data']['i18n_strings'] = [
+      [
+        'lid' => 1,
+        'objectid' => 139,
+        'type' => 'item',
+        'property' => 'title',
+        'objectindex' => 0,
+        'format' => 0,
+      ],
+      [
+        'lid' => 2,
+        'objectid' => 139,
+        'type' => 'item',
+        'property' => 'description',
+        'objectindex' => 0,
+        'format' => 0,
+      ],
+      [
+        'lid' => 3,
+        'objectid' => 140,
+        'type' => 'item',
+        'property' => 'description',
+        'objectindex' => 0,
+        'format' => 0,
+      ],
+      [
+        'lid' => 4,
+        'objectid' => 141,
+        'type' => 'item',
+        'property' => 'title',
+        'objectindex' => 0,
+        'format' => 0,
+      ],
+    ];
+    $test[0]['source_data']['locales_target'] = [
+      [
+        'lid' => 1,
+        'language' => 'fr',
+        'translation' => 'fr - title translation',
+        'plid' => 0,
+        'plural' => 0,
+        'u18n_status' => 0,
+      ],
+      [
+        'lid' => 2,
+        'language' => 'fr',
+        'translation' => 'fr - description translation',
+        'plid' => 0,
+        'plural' => 0,
+        'u18n_status' => 0,
+      ],
+      [
+        'lid' => 3,
+        'language' => 'zu',
+        'translation' => 'zu - description translation',
+        'plid' => 0,
+        'plural' => 0,
+        'u18n_status' => 0,
+      ],
+      [
+        'lid' => 4,
+        'language' => 'zu',
+        'translation' => 'zu - title translation',
+        'plid' => 0,
+        'plural' => 0,
+        'u18n_status' => 0,
+      ],
+    ];
+
+    $test[0]['expected_results'] = [
+      [
+        'menu_name' => 'menu-test-menu',
+        'mlid' => 139,
+        'property' => 'title',
+        'language' => 'fr',
+        'title_untranslated' => 'Test 2',
+        'description_untranslated' => 'Test menu link 2',
+        'title_translated' => 'fr - title translation',
+        'description_translated' => 'fr - description translation',
+
+      ],
+      [
+        'menu_name' => 'menu-test-menu',
+        'mlid' => 139,
+        'property' => 'description',
+        'language' => 'fr',
+        'title_untranslated' => 'Test 2',
+        'description_untranslated' => 'Test menu link 2',
+        'title_translated' => 'fr - title translation',
+        'description_translated' => 'fr - description translation',
+      ],
+      [
+        'menu_name' => 'menu-test-menu',
+        'mlid' => 140,
+        'description' => 'Test menu link 2',
+        'property' => 'description',
+        'language' => 'zu',
+        'title_untranslated' => 'Test 2',
+        'description_untranslated' => 'Test menu link 2',
+        'title_translated' => NULL,
+        'description_translated' => 'zu - description translation',
+      ],
+      [
+        'menu_name' => 'menu-test-menu',
+        'mlid' => 141,
+        'property' => 'title',
+        'language' => 'zu',
+        'title_untranslated' => 'Test 3',
+        'description_untranslated' => 'Test menu link 3',
+        'title_translated' => 'zu - title translation',
+        'description_translated' => NULL,
+      ],
+    ];
+
+    return $test;
+  }
+
+}