diff -u b/core/modules/system/system.module b/core/modules/system/system.module
--- b/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -870,10 +870,10 @@
             $info[$module] = $data[$module]->info;
           }
         }
-        // Store the module info in cache. We rely on consecutive calls to
-        // system_rebuild_module_data() to reset this key, such as when
-        // listing modules, (un)installating modules, importing configuration,
-        // updating the site and when flushing all caches.
+        // Store the module information in cache. This cache is cleared by
+        // calling system_rebuild_module_data(), for example, when listing
+        // modules, (un)installing modules, importing configuration, updating
+        // the site and when flushing all the caches.
         \Drupal::cache()->set('system.module.info', $info);
       }
     }
@@ -1016,8 +1016,8 @@
     $modules = \Drupal::moduleHandler()->buildModuleDependencies($modules);
     $modules_cache = $modules;
 
-    // Store filenames to allow drupal_get_filename() to
-    // retrieve them without having to rebuild or scan the filesystem.
+    // Store filenames to allow drupal_get_filename() to retrieve them without
+    // having to rebuild or scan the filesystem.
     \Drupal::state()->set('system.module.files', $files);
     // Clear the module info cache.
     \Drupal::cache()->delete('system.module.info');