diff --git a/core/modules/hal/config/install/hal.settings.yml b/core/modules/hal/config/install/hal.settings.yml
index 1c895c1718..8e8ef71850 100644
--- a/core/modules/hal/config/install/hal.settings.yml
+++ b/core/modules/hal/config/install/hal.settings.yml
@@ -1,4 +1,8 @@
 # Set the domain for HAL type and relation links.
 # If left blank, the site's domain will be used.
 link_domain: ~
+# Before Drupal 8.5, the file URI field value was overridden to only return the
+# full file URL. The default for new sites is now to return the actual URI value
+# as well as a root relative file path. Enable this setting to use the previous
+# behavior.
 bc_file_uri_as_url_normalizer: false
diff --git a/core/modules/hal/hal.install b/core/modules/hal/hal.install
index 0dc3fd566d..5741c1258d 100644
--- a/core/modules/hal/hal.install
+++ b/core/modules/hal/hal.install
@@ -41,5 +41,5 @@ function hal_update_8501() {
     ->set('bc_file_uri_as_url_normalizer', TRUE)
     ->save(TRUE);
 
-  return t('The REST API will no longer return the full URL for file entity URI values for HAL+JSON responses. It will return the URI value itself, with an additional URL property providing a root relative file path. If your site depends on these value being strings, <a href="https://www.drupal.org/node/2925783">read the change record to learn how to enable the BC mode.</a>');
+  return t('BC Mode has been enabled for file URI normalization. Only the full file URL will be returned <a href="https://www.drupal.org/node/2925783">read the change record for more information about opting out of this behavior.</a>');
 }