diff --git a/core/modules/locale/config/locale.settings.yml b/core/modules/locale/config/locale.settings.yml
new file mode 100644
index 0000000..d606901
--- /dev/null
+++ b/core/modules/locale/config/locale.settings.yml
@@ -0,0 +1,3 @@
+translation:
+  check_disabled_modules: false
+  default_server_pattern: 'http://ftp.drupal.org/files/translations/%core/%project/%project-%version.%language.po'
diff --git a/core/modules/locale/lib/Drupal/locale/Tests/LocaleCompareTest.php b/core/modules/locale/lib/Drupal/locale/Tests/LocaleCompareTest.php
index 25d5e71..2e85afa 100644
--- a/core/modules/locale/lib/Drupal/locale/Tests/LocaleCompareTest.php
+++ b/core/modules/locale/lib/Drupal/locale/Tests/LocaleCompareTest.php
@@ -54,21 +54,24 @@ class LocaleCompareTest extends WebTestBase {
     $this->assertEqual($projects['locale_test']['info']['interface translation server pattern'], 'core/modules/locale/test/modules/locale_test/%project-%version.%language.po', 'Interface translation parameter found in project info.');
     $this->assertEqual($projects['locale_test']['name'] , 'locale_test', format_string('%key found in project info.', array('%key' => 'interface translation project')));
 
+    // Get the locale settings.
+    $config = config('locale.settings');
+
     // Check if disabled modules are detected.
-    variable_set('locale_translation_check_disabled', TRUE);
+    $config->set('translation.check_disabled_modules', TRUE)->save();
     drupal_static_reset('locale_translation_project_list');
     $projects = locale_translation_project_list();
     $this->assertTrue(isset($projects['locale_test_disabled']), 'Disabled module found');
 
     // Check the fully processed list of project data of both enabled and
     // disabled modules.
-    variable_set('locale_translation_check_disabled', TRUE);
+    $config->set('translation.check_disabled_modules', TRUE)->save();
     drupal_static_reset('locale_translation_project_list');
     $projects = locale_translation_get_projects();
     $this->assertEqual($projects['drupal']->name, 'drupal', 'Core project found');
     $this->assertEqual($projects['locale_test']->server_pattern, 'core/modules/locale/test/modules/locale_test/%project-%version.%language.po', 'Interface translation parameter found in project info.');
     $this->assertEqual($projects['locale_test_disabled']->status, '0', 'Disabled module found');
-    variable_del('locale_translation_check_disabled');
+    $config->delete('translation.check_disabled_modules');
 
     // Return the locale test modules back to their hidden state.
     variable_del('locale_translation_test_system_info_alter');
diff --git a/core/modules/locale/locale.api.php b/core/modules/locale/locale.api.php
index 9aabb0e..b561ea0 100644
--- a/core/modules/locale/locale.api.php
+++ b/core/modules/locale/locale.api.php
@@ -11,15 +11,15 @@
  *
  * .info file properties for interface translation settings.
  *
- * Modules hosted on drupal.org, a project definition is automatically added to
- * the .info file. Only modules with this project definition are discovered by
- * the update module and use it to check for new releases. Locale module uses
- * the same data to build a list of module to check for new translations.
+ * For modules hosted on drupal.org, a project definition is automatically added
+ * to the .info file. Only modules with this project definition are discovered
+ * by the update module and use it to check for new releases. Locale module uses
+ * the same data to build a list of modules to check for new translations.
  * Therefore modules not hosted at drupal.org, such as custom modules, custom
  * themes, features and distributions, need a way to identify themselves to
  * the Locale module if they have translations that require to be updated.
  *
- * Custom module which contain new strings should provide po file(s) containing
+ * Custom modules which contain new strings should provide po file(s) containing
  * source strings and string translations in gettext format. The translation
  * file can be located both local and remote. Use the following .info file
  * properties to inform Locale module to load and import the translations.
@@ -78,11 +78,13 @@
  * Alter the list of projects to be updated by locale's interface translation.
  *
  * Locale module attempts to update the translation of those modules returned
- * by update_get_projects(). Using this hook the data returned by
+ * by update_get_projects(). Using this hook, the data returned by
  * update_get_projects() can be altered or extended.
  *
  * Modules or distributions that use a dedicated translation server should use
- * this hook to specify the interface translation server pattern.
+ * this hook to specify the interface translation server pattern, or to add
+ * additional custom/non-Drupal.org modules to the list of modules known to
+ * locale.
  * - "interface translation server pattern": URL of the .po translation files
  *   used to download the files from. The URL contains tokens which will be
  *   replaced by appropriate values.
diff --git a/core/modules/locale/locale.compare.inc b/core/modules/locale/locale.compare.inc
index 55597d1..039eba3 100644
--- a/core/modules/locale/locale.compare.inc
+++ b/core/modules/locale/locale.compare.inc
@@ -37,14 +37,15 @@ function locale_translation_get_projects() {
 
   if (empty($projects)) {
     // Get project data from the database.
-    $projects = array();
-    $result = db_query('SELECT * FROM {locale_project}');
+    $result = db_query('SELECT name, project_type, core, version, server_pattern, status FROM {locale_project}');
 
+    // http://drupal.org/node/1777106 is a follow-up issue to make the check for
+    // possible out-of-date project information more robust.
     if ($result->rowCount() == 0 && module_exists('update')) {
       // At least the core project should be in the database, so we build the
       // data if none are found.
       locale_translation_build_projects();
-      $result = db_query('SELECT * FROM {locale_project}');
+      $result = db_query('SELECT name, project_type, core, version, server_pattern, status FROM {locale_project}');
     }
 
     foreach ($result as $project) {
@@ -77,6 +78,8 @@ function locale_translation_flush_projects() {
  *   - "project_type": Project type, e.g. 'module', 'theme'.
  *   - "core": Core release version, e.g. 8.x
  *   - "version": Project release version, e.g. 8.x-1.0
+ *     See http://drupalcode.org/project/drupalorg.git/blob/refs/heads/7.x-3.x:/drupalorg_project/plugins/release_packager/DrupalorgProjectPackageRelease.class.php#l219
+ *     for how the version strings are created.
  *   - "server_pattern": Translation server po file pattern.
  *   - "status": Project status, 1 = enabled.
  */
@@ -98,6 +101,7 @@ function locale_translation_build_projects() {
 
   $default_server = locale_translation_default_translation_server();
 
+  // If project is a dev release, or core, find the latest available release.
   $project_updates = update_get_available(TRUE);
   foreach ($projects as $name => $data) {
     if (isset($project_updates[$name]['releases']) && $project_updates[$name]['project_status'] != 'not-fetched') {
@@ -107,6 +111,7 @@ function locale_translation_build_projects() {
         foreach ($project_updates[$name]['releases'] as $project_release) {
           // The first release with the same major release number which is not a
           // dev release is the one. Releases are sorted the most recent first.
+          // @todo http://drupal.org/node/1774024 Make a helper function.
           if ($project_release['version_major'] == $matches[1] &&
               (!isset($project_release['version_extra']) || $project_release['version_extra'] != 'dev')) {
             $release = $project_release;
@@ -114,7 +119,8 @@ function locale_translation_build_projects() {
           }
         }
       }
-      elseif ($name == "drupal" || preg_match("/HEAD/", $data['info']['version'], $matches)) {
+      // If project is not a dev version, but is core, pick latest release.
+      elseif ($name == "drupal") {
         // Pick latest available release.
         $release = array_shift($project_updates[$name]['releases']);
       }
@@ -126,13 +132,14 @@ function locale_translation_build_projects() {
       unset($release);
     }
 
+    // For every project store information.
     $data += array(
       'version' => isset($data['info']['version']) ? $data['info']['version'] : '',
       'core' => isset($data['info']['core']) ? $data['info']['core'] : DRUPAL_CORE_COMPATIBILITY,
       // A project can provide the path and filename pattern to download the
       // gettext file. Use the default if not.
       'server_pattern' => isset($data['info']['interface translation server pattern']) ? $data['info']['interface translation server pattern'] : $default_server['pattern'],
-      'status' => $data['project_status'] ? 1 : 0,
+      'status' => !empty($data['project_status']) ? 1 : 0,
     );
     $project = (object) $data;
     $projects[$name] = $project;
@@ -168,6 +175,7 @@ function locale_translation_project_list() {
   $projects = &drupal_static(__FUNCTION__, array());
   if (empty($projects)) {
     module_load_include('compare.inc', 'update');
+    $config = config('locale.settings');
     $projects = array();
 
     $additional_whitelist = array(
@@ -178,7 +186,7 @@ function locale_translation_project_list() {
     $theme_data = _locale_translation_prepare_project_list(system_rebuild_theme_data(), 'theme');
     update_process_info_list($projects, $module_data, 'module', TRUE, $additional_whitelist);
     update_process_info_list($projects, $theme_data, 'theme', TRUE, $additional_whitelist);
-    if (variable_get('locale_translation_check_disabled', 0)) {
+    if ($config->get('translation.check_disabled_modules')) {
       update_process_info_list($projects, $module_data, 'module', FALSE, $additional_whitelist);
       update_process_info_list($projects, $theme_data, 'theme', FALSE, $additional_whitelist);
     }
@@ -195,6 +203,7 @@ function locale_translation_project_list() {
  * Modify .info file data before it is processed by update_process_info_list().
  * In order for update_process_info_list() to recognize a project, it requires
  * the 'project' parameter in the .info file data.
+ *
  * Custom modules or themes can bring their own gettext translation file. To
  * enable import of this file the module or theme defines "interface translation
  * project = myproject" in its .info file. This function will add a project
@@ -210,13 +219,9 @@ function locale_translation_project_list() {
  */
 function _locale_translation_prepare_project_list($data, $type) {
   foreach ($data as $name => $file) {
-    // Include interface translation projects.
-    // Custom modules can bring their own gettext translation file.
-    // To enable import of this file the module must define
-    // 'interface translation project = myproject' in its .info file.
-    // To allow update_process_info_list() to identify this as a project
-    // the 'project' property is filled with the 'interface translation project'
-    // value.
+    // Include interface translation projects. To allow
+    // update_process_info_list() to identify this as a project the 'project'
+    // property is filled with the 'interface translation project' value.
     if (isset($file->info['interface translation project'])) {
       $data[$name]->info['project'] = $file->info['interface translation project'];
     }
@@ -232,8 +237,9 @@ function _locale_translation_prepare_project_list($data, $type) {
  *   - "server_pattern": URL containing po file pattern.
  */
 function locale_translation_default_translation_server() {
+  $config = config('locale.settings');
   return array(
-    'pattern' => variable_get('locale_translation_default_server_pattern', LOCALE_TRANSLATION_DEFAULT_SERVER_PATTERN),
+    'pattern' => $config->get('translation.default_server_pattern'),
   );
 }
 
diff --git a/core/modules/locale/locale.install b/core/modules/locale/locale.install
index 35c8185..e2540c0 100644
--- a/core/modules/locale/locale.install
+++ b/core/modules/locale/locale.install
@@ -32,9 +32,6 @@ function locale_uninstall() {
   variable_del('locale_cache_length');
   variable_del('locale_translation_plurals');
   variable_del('locale_translation_javascript');
-  variable_del('locale_translation_test_system_info_alter');
-  variable_del('locale_translation_check_disabled');
-  variable_del('locale_translation_default_server_pattern');
 
   // Remove all node type language variables. Node module might have been
   // enabled, but may be disabled, so use a wildcard delete.
@@ -172,20 +169,22 @@ function locale_schema() {
         'not null' => TRUE,
       ),
       'project_type' => array(
-        'description' => 'Project type, may be core, module, theme',
+        'description' => 'Project type: core, module, or theme.',
         'type' => 'varchar',
         'length' => 15,
         'not null' => TRUE,
       ),
       'core' => array(
-        'description' => 'Core compatibility string for this project.',
+        // http://drupal.org/node/542202#core has an example.
+        'description' => 'Core compatibility string for this project, for example: 8.x',
         'type' => 'varchar',
         'length' => 4,
         'not null' => TRUE,
         'default' => '',
       ),
       'version' => array(
-        'description' => 'The version release of the project.',
+        // http://drupal.org/node/467026 has examples.
+        'description' => 'The version release of the project, for example: 8.x-2.1 or 8.x-1.0-dev',
         'type' => 'varchar',
         'length' => 128,
         'not null' => TRUE,
@@ -199,7 +198,8 @@ function locale_schema() {
         'default' => '',
       ),
       'status' => array(
-        'description' => 'The update status of the project.',
+        // locale.compare.inc gives possible values for status.
+        'description' => 'The status of the project. Possible values are: 1 = enabled, 0 = disabled.',
         'type' => 'int',
         'not null' => TRUE,
         'default' => 1,
@@ -679,59 +679,9 @@ function locale_update_8010() {
  */
 function locale_update_8011() {
   // Add a 'locale' cache table.
-  db_create_table('cache_locale', array(
-    'description' => 'Cache table for the locale module to store various data.',
-    'fields' => array(
-      'cid' => array(
-        'description' => 'Primary Key: Unique cache ID.',
-        'type' => 'varchar',
-        'length' => 255,
-        'not null' => TRUE,
-        'default' => '',
-      ),
-      'data' => array(
-        'description' => 'A collection of data to cache.',
-        'type' => 'blob',
-        'not null' => FALSE,
-        'size' => 'big',
-      ),
-      'expire' => array(
-        'description' => 'A Unix timestamp indicating when the cache entry should expire, or 0 for never.',
-        'type' => 'int',
-        'not null' => TRUE,
-        'default' => 0,
-      ),
-      'created' => array(
-        'description' => 'A Unix timestamp indicating when the cache entry was created.',
-        'type' => 'int',
-        'not null' => TRUE,
-        'default' => 0,
-      ),
-      'serialized' => array(
-        'description' => 'A flag to indicate whether content is serialized (1) or not (0).',
-        'type' => 'int',
-        'size' => 'small',
-        'not null' => TRUE,
-        'default' => 0,
-      ),
-      'tags' => array(
-        'description' => 'Space-separated list of cache tags for this entry.',
-        'type' => 'text',
-        'size' => 'big',
-        'not null' => FALSE,
-      ),
-      'checksum' => array(
-        'description' => 'The tag invalidation sum when this entry was saved.',
-        'type' => 'int',
-        'not null' => TRUE,
-        'default' => 0,
-      ),
-    ),
-    'indexes' => array(
-      'expire' => array('expire'),
-    ),
-    'primary key' => array('cid'),
-  ));
+  $locale_cache_schema = system_schema_cache_8001();
+  $locale_cache_schema['description'] = 'Cache table for the locale module to store various data.';
+  db_create_table('cache_locale', $locale_cache_schema);
 
   // Add locale_project table.
   db_create_table('locale_project', array(
diff --git a/core/modules/locale/tests/modules/locale_test/locale_test.install b/core/modules/locale/tests/modules/locale_test/locale_test.install
new file mode 100644
index 0000000..364f9fe
--- /dev/null
+++ b/core/modules/locale/tests/modules/locale_test/locale_test.install
@@ -0,0 +1,14 @@
+<?php
+
+/**
+ * @file
+ * Install, update and uninstall functions for the locale_test module.
+ */
+
+/**
+ * Implements hook_uninstall().
+ */
+function locale_test_uninstall() {
+  // Clear variables.
+  variable_del('locale_translation_test_system_info_alter');
+}
diff --git a/core/modules/locale/tests/modules/locale_test/locale_test.module b/core/modules/locale/tests/modules/locale_test/locale_test.module
index 6044a07..4aa4d5d 100644
--- a/core/modules/locale/tests/modules/locale_test/locale_test.module
+++ b/core/modules/locale/tests/modules/locale_test/locale_test.module
@@ -21,7 +21,7 @@ function locale_test_system_info_alter(&$info, $file, $type) {
   }
 
   if ($file->name == 'locale_test' || $file->name == 'locale_test_disabled') {
-    // Make the module appear as not-disabled.
+    // Make the module appear as unhidden.
     $info['hidden'] = FALSE;
   }
 }
diff --git a/core/modules/locale/tests/modules/locale_test_disabled/locale_test_disabled.module b/core/modules/locale/tests/modules/locale_test_disabled/locale_test_disabled.module
index a80d9da..0003e96 100644
--- a/core/modules/locale/tests/modules/locale_test_disabled/locale_test_disabled.module
+++ b/core/modules/locale/tests/modules/locale_test_disabled/locale_test_disabled.module
@@ -2,5 +2,5 @@
 
 /**
  * @file
- * Simulate a disabled contrib for Locale test scripts.
+ * Simulate a disabled contrib module for Locale test scripts.
  */
diff --git a/core/modules/system/system.install b/core/modules/system/system.install
index ac983aa..83217be 100644
--- a/core/modules/system/system.install
+++ b/core/modules/system/system.install
@@ -1472,6 +1472,68 @@ function system_schema() {
   return $schema;
 }
 
+/**
+ * The cache schema corresponding to Drupal 8.0.
+ *
+ * Helper function to add cache tables in the Drupal 7 to 8 upgrade path
+ * without relying on system_schema(), which may change with future updates.
+ */
+function system_schema_cache_8007() {
+  return array(
+    'description' => 'Generic cache table for caching things not separated out into their own tables. Contributed modules may also use this to store cached items.',
+    'fields' => array(
+      'cid' => array(
+        'description' => 'Primary Key: Unique cache ID.',
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => TRUE,
+        'default' => '',
+      ),
+      'data' => array(
+        'description' => 'A collection of data to cache.',
+        'type' => 'blob',
+        'not null' => FALSE,
+        'size' => 'big',
+      ),
+      'expire' => array(
+        'description' => 'A Unix timestamp indicating when the cache entry should expire, or 0 for never.',
+        'type' => 'int',
+        'not null' => TRUE,
+        'default' => 0,
+      ),
+      'created' => array(
+        'description' => 'A Unix timestamp indicating when the cache entry was created.',
+        'type' => 'int',
+        'not null' => TRUE,
+        'default' => 0,
+      ),
+      'serialized' => array(
+        'description' => 'A flag to indicate whether content is serialized (1) or not (0).',
+        'type' => 'int',
+        'size' => 'small',
+        'not null' => TRUE,
+        'default' => 0,
+      ),
+      'tags' => array(
+        'description' => 'Space-separated list of cache tags for this entry.',
+        'type' => 'text',
+        'size' => 'big',
+        'not null' => FALSE,
+      ),
+      'checksum' => array(
+        'description' => 'The tag invalidation sum when this entry was saved.',
+        'type' => 'int',
+        'not null' => TRUE,
+        'default' => 0,
+      ),
+    ),
+    'indexes' => array(
+      'expire' => array('expire'),
+    ),
+    'primary key' => array('cid'),
+  );
+}
+
 // Updates for core.
 
 function system_update_last_removed() {