diff --git a/src/wp-includes/canonical.php b/src/wp-includes/canonical.php
index 34bb774d45..2afc1fec1b 100644
--- a/src/wp-includes/canonical.php
+++ b/src/wp-includes/canonical.php
@@ -602,6 +602,12 @@ function redirect_guess_404_permalink() {
 }
 
 /**
+ * Redirects a variety of shorthand URLs to the admin.
+ *
+ * If a user visits example.com/admin, they'll be redirected to /wp-admin.
+ * Visiting /login redirects to /wp-login.php, and so on.
+ *
+ * @since 3.4.0
  *
  * @global WP_Rewrite $wp_rewrite
  */