diff --git a/core/lib/Drupal/Component/PhpStorage/MTimeProtectedFastFileStorage.php b/core/lib/Drupal/Component/PhpStorage/MTimeProtectedFastFileStorage.php
index 87d9d2a..de55d3a 100644
--- a/core/lib/Drupal/Component/PhpStorage/MTimeProtectedFastFileStorage.php
+++ b/core/lib/Drupal/Component/PhpStorage/MTimeProtectedFastFileStorage.php
@@ -49,6 +49,10 @@ class MTimeProtectedFastFileStorage extends FileStorage {
   /**
    * The maximum number of characters of the hash to use for uniqueness.
    *
+   * Many file functions in PHP for Windows limit paths to 260 characters. Until
+   * this is fxied, we limit the length of the hash used in generating the
+   * directory and filenames.
+   *
    * @var int
    */
   protected $maxHashLength = 10;
diff --git a/core/lib/Drupal/Core/Template/TwigPhpStorageCache.php b/core/lib/Drupal/Core/Template/TwigPhpStorageCache.php
index 4d07643..63f1814 100644
--- a/core/lib/Drupal/Core/Template/TwigPhpStorageCache.php
+++ b/core/lib/Drupal/Core/Template/TwigPhpStorageCache.php
@@ -46,6 +46,10 @@ class TwigPhpStorageCache implements \Twig_CacheInterface {
   /**
    * The maximum number of characters of the hash to use for uniqueness.
    *
+   * Many file functions in PHP for Windows limit paths to 260 characters. Until
+   * this is fxied, we limit the length of the hash used in generating the
+   * directory and filenames.
+   *
    * @var int
    */
   protected $maxHashLength = 10;