diff --git a/core/modules/system/theme.api.php b/core/modules/system/theme.api.php
index 7a2181d..6862e2a 100644
--- a/core/modules/system/theme.api.php
+++ b/core/modules/system/theme.api.php
@@ -158,7 +158,7 @@
  * suggestions as input, and can change this array (adding suggestions and
  * removing them).
  *
- * @section Assets
+ * @section assets Assets
  *
  * We can distinguish between three types of assets:
  * 1. unconditional page-level assets (loaded on all pages where the theme is in