diff --git a/core/lib/Drupal/Core/Theme/Registry.php b/core/lib/Drupal/Core/Theme/Registry.php
index aa07fa9..8c9efb3 100644
--- a/core/lib/Drupal/Core/Theme/Registry.php
+++ b/core/lib/Drupal/Core/Theme/Registry.php
@@ -448,9 +448,9 @@ protected function processExtension(&$cache, $name, $type, $theme, $path) {
           $result[$hook]['includes'][] = $include_file;
         }
 
-        // Templates are the default implementation for a theme hook. If a
-        // theme hook provides a theme function callback, check to ensure that
-        // it actually exists.
+        // A template file is the default implementation for a theme hook, but
+        // if the theme hook specifies a function callback instead, check to
+        // ensure the function actually exists.
         if (isset($info['function']) && !function_exists($info['function'])) {
           throw new \BadFunctionCallException(sprintf(
             'Theme hook "%s" refers to a theme function callback that does not exist: "%s"',
diff --git a/core/modules/system/system.api.php b/core/modules/system/system.api.php
index f80f9bd..c6a2281 100644
--- a/core/modules/system/system.api.php
+++ b/core/modules/system/system.api.php
@@ -980,22 +980,20 @@ function hook_help($route_name, \Drupal\Core\Routing\RouteMatchInterface $route_
  *     theme path will be used, but if the file will not be in the default
  *     path, include it here. This path should be relative to the Drupal root
  *     directory.
- *   - template: If specified, this theme implementation is a template, and
- *     this is the template file without an extension. If neither 'template'
- *     nor 'function' is specified, a default template name will be assumed.
- *     For example, if a module registers the 'search_result' theme hook,
- *     'search-result' will be assigned to its template. Do not put .html.twig
- *     on this file, that extension will be added automatically by the default
- *     rendering engine (which is Twig). If 'path' above is specified, the
- *     template should also be in this path.
+ *   - template: If specified, the theme implementation is a template file, and
+ *     this is the template name. Do not add 'html.twig' on the end of the
+ *     template name. The extension will be added automatically by the default
+ *     rendering engine (which is Twig.) If 'path' is specified, 'template'
+ *     should also be specified. If neither 'template' nor 'function' are
+ *     specified, a default template name will be assumed. For example, if a
+ *     module registers the 'search_result' theme hook, 'search-result' will be
+ *     assigned as its template name.
  *   - function: If specified, this will be the function name to invoke for
  *     this implementation. If neither 'template' nor 'function' is specified,
- *     a default template name will be assumed. For example, if a module
- *     registers the 'search_result' theme hook, 'search-result' will be
- *     assigned to its template. Do not put .html.twig on this file,
- *     that extension will be added automatically by the default
- *     rendering engine (which is Twig). If 'path' above is specified, the
- *     template should also be in this path.
+ *     a default template name will be assumed. If neither 'template' nor
+ *     'function' are specified, a default template name will be assumed. For
+ *     example, if a module registers the 'search_result' theme hook,
+ *     'search-result' will be assigned as its template name.
  *   - base hook: Used for _theme() suggestions only: the base theme hook name.
  *     Instead of this suggestion's implementation being used directly, the base
  *     hook will be invoked with this implementation as its first suggestion.
diff --git a/core/modules/views/views.module b/core/modules/views/views.module
index 12aaa14..dda2b55 100644
--- a/core/modules/views/views.module
+++ b/core/modules/views/views.module
@@ -166,9 +166,9 @@ function views_theme($existing, $type, $theme, $path) {
       if (!isset($def['theme']) || empty($def['register_theme'])) {
         continue;
       }
-      // For each theme registration we a base directory to look for the
-      // templates folder. This will be in any case the root of the given module
-      // so we always need a module definition.
+      // For each theme registration, we have a base directory to check for the
+      // templates folder. This will be relative to the root of the given module
+      // folder, so we always need a module definition.
       // @todo: watchdog or exception?
       if (!isset($def['provider']) || !$module_handler->moduleExists($def['provider'])) {
         continue;
@@ -196,7 +196,7 @@ function views_theme($existing, $type, $theme, $path) {
         $hooks[$def['theme']]['file'] = $def['theme_file'];
       }
 
-      // Whenever we got a theme file, we include it directly so we can
+      // Whenever we have a theme file, we include it directly so we can
       // auto-detect the theme function.
       if (isset($def['theme_file'])) {
         $include = DRUPAL_ROOT . '/' . $module_dir . '/' . $def['theme_file'];