diff --git a/core/lib/Drupal/Core/Config/ConfigInstaller.php b/core/lib/Drupal/Core/Config/ConfigInstaller.php
index 205f270..58b189d 100644
--- a/core/lib/Drupal/Core/Config/ConfigInstaller.php
+++ b/core/lib/Drupal/Core/Config/ConfigInstaller.php
@@ -161,7 +161,7 @@ protected function listDefaultConfigCollection($collection, $type, $name, array
         if (in_array($config_name, $config_to_install)) {
           return FALSE;
         }
-        // Ensure the configuration is provided by an enabled module
+        // Ensure the configuration is provided by an enabled module.
         $provider = Unicode::substr($config_name, 0, strpos($config_name, '.'));
         return in_array($provider, $enabled_extensions);
       });
@@ -341,7 +341,7 @@ public function findPreExistingConfiguration($type, $name) {
     $collection_info = $this->configManager->getConfigCollectionInfo();
 
     // Read enabled extensions directly from configuration to avoid circular
-    // dependencies with ModuleHandler and ThemeHandler.
+    // dependencies on ModuleHandler and ThemeHandler.
     $extension_config = $this->configFactory->get('core.extension');
     $enabled_extensions = array_keys((array) $extension_config->get('module'));
     $enabled_extensions += array_keys((array) $extension_config->get('theme'));
diff --git a/core/lib/Drupal/Core/Config/PreExistingConfigException.php b/core/lib/Drupal/Core/Config/PreExistingConfigException.php
index eabb7f0..d34a7ad 100644
--- a/core/lib/Drupal/Core/Config/PreExistingConfigException.php
+++ b/core/lib/Drupal/Core/Config/PreExistingConfigException.php
@@ -8,7 +8,7 @@
 namespace Drupal\Core\Config;
 
 /**
- * An exception thrown if configuration already exists with the same name.
+ * An exception thrown if configuration with the same name already exists.
  */
 class PreExistingConfigException extends ConfigException {
 }
diff --git a/core/lib/Drupal/Core/Extension/ModuleInstaller.php b/core/lib/Drupal/Core/Extension/ModuleInstaller.php
index a8610b1..eaacec9 100644
--- a/core/lib/Drupal/Core/Extension/ModuleInstaller.php
+++ b/core/lib/Drupal/Core/Extension/ModuleInstaller.php
@@ -131,7 +131,8 @@ public function install(array $module_list, $enable_dependencies = TRUE) {
           )));
         }
 
-        // Profiles can not have config clashes.
+        // Install profiles can not have config clashes as if they contain
+        // configuration with the same name as a module it will override it.
         if ($module != drupal_get_profile()) {
           // Validate default configuration of this module. Bail if unable to
           // install. Should not continue installing more modules because those
diff --git a/core/modules/forum/config/install/taxonomy.vocabulary.forums.yml b/core/modules/forum/config/install/taxonomy.vocabulary.forums.yml
index 6ed487b..951e4a3 100644
--- a/core/modules/forum/config/install/taxonomy.vocabulary.forums.yml
+++ b/core/modules/forum/config/install/taxonomy.vocabulary.forums.yml
@@ -1,6 +1,9 @@
 langcode: en
 status: true
-dependencies: {  }
+dependencies:
+  enforced:
+    module:
+      - forum
 name: Forums
 vid: forums
 description: 'Forum navigation vocabulary'
diff --git a/core/modules/system/src/Controller/ConfigClashController.php b/core/modules/system/src/Controller/ConfigClashController.php
index 43c58e9..158b800 100644
--- a/core/modules/system/src/Controller/ConfigClashController.php
+++ b/core/modules/system/src/Controller/ConfigClashController.php
@@ -61,6 +61,8 @@ class ConfigClashController extends ControllerBase {
    *   The key value expirable factory.
    * @param \Drupal\Core\Config\ConfigManagerInterface $config_manager
    *   The configuration manager.
+   * @param \Drupal\Core\Config\ConfigInstallerInterface $config_installer
+   *   The configuration installer.
    */
   public function __construct(KeyValueStoreExpirableInterface $key_value_expirable, ConfigManagerInterface $config_manager, ConfigInstallerInterface $config_installer) {
     $this->keyValueExpirable = $key_value_expirable;
@@ -122,7 +124,7 @@ public function moduleReport() {
    *   The report as a render array.
    */
   protected function report($type, array $extensions) {
-    // Check if we have any pre existing configuration.
+    // Check if we have any pre-existing configuration.
     $existing_configuration = array();
     foreach ($extensions as $extension) {
       $existing_configuration = array_merge_recursive($this->configInstaller->findPreExistingConfiguration($type, $extension), $existing_configuration);
@@ -152,10 +154,14 @@ protected function report($type, array $extensions) {
             }
           }
           else {
-            // Super weird.
+            // @todo: Work out
+            $report['config_clashes']['#items'][] = $config_name;
           }
         }
       }
+      $report['debug'] = array(
+        '#markup' => '<p>' . print_r($existing_configuration, TRUE) . '</p>',
+      );
     }
 
     return $report;
diff --git a/core/modules/system/src/Form/ModulesListForm.php b/core/modules/system/src/Form/ModulesListForm.php
index 5608a3a..2be620b 100644
--- a/core/modules/system/src/Form/ModulesListForm.php
+++ b/core/modules/system/src/Form/ModulesListForm.php
@@ -508,7 +508,7 @@ public function submitForm(array &$form, FormStateInterface $form_state) {
     // Retrieve a list of modules to install and their dependencies.
     $modules = $this->buildModuleList($form_state);
 
-    // Check if we have any pre existing configuration.
+    // Check if we have any pre-existing configuration.
     $existing_configuration = array();
     foreach (array_keys($modules['install']) as $module) {
       $existing_configuration = array_merge_recursive($this->configInstaller->findPreExistingConfiguration('module', $module), $existing_configuration);
diff --git a/core/modules/system/system.routing.yml b/core/modules/system/system.routing.yml
index d5d134a..23c9aa5 100644
--- a/core/modules/system/system.routing.yml
+++ b/core/modules/system/system.routing.yml
@@ -288,7 +288,7 @@ system.theme_install:
 system.modules_config_clash:
   path: 'admin/modules/config_clash'
   defaults:
-    _content: 'Drupal\system\Controller\ConfigClashController::moduleReport'
+    _controller: 'Drupal\system\Controller\ConfigClashController::moduleReport'
     _title: 'Configuration clash'
   requirements:
     _permission: 'administer modules'