diff --git a/core/modules/system/core.api.php b/core/modules/system/core.api.php
index 6c3dca8..891d796 100644
--- a/core/modules/system/core.api.php
+++ b/core/modules/system/core.api.php
@@ -1869,8 +1869,10 @@ function hook_display_variant_plugin_alter(array &$definitions) {
  * priority of your event subscriber (see terminate example above). Event
  * subscribers with higher priority numbers get executed first; the default
  * priority is zero. If two event subscribers for the same event have the same
- * priority, the module weight of the modules that define the subscriber
- * services will be used to break the tie. In case there is still a tie, the
- * order will be alphabetical by the subscriber class name (with namespace).
+ * priority, the one defined in a module with a lower module weight will fire
+ * first. Subscribers defined in the same services file are fired in
+ * definition order. If order matters defining a priority is strongly advised
+ * instead of relying on these two tie breaker rules as they might change in a
+ * minor release.
  * @}
  */