diff --git a/wp-admin/network.php b/wp-admin/network.php
index cdef7f4067..9ba4d463fe 100644
--- a/wp-admin/network.php
+++ b/wp-admin/network.php
@@ -58,13 +58,20 @@ function allow_subdomain_install() {
 	return true;
 }
 /**
- * Allow subdirectory install
+ * Allow subdirectory install.
  *
  * @since 3.0.0
  * @return bool Whether subdirectory install is allowed
  */
 function allow_subdirectory_install() {
 	global $wpdb;
+        /**
+         * Filter whether to enable the subdirectory install feature in Multisite.
+         * 
+         * @since 3.0.0
+         * 
+         * @param bool true Whether to enable the subdirectory install feature in Multisite. Default is false.
+         */
 	if ( apply_filters( 'allow_subdirectory_install', false ) )
 		return true;