diff --git a/core/modules/email/config/schema/email.schema.yml b/core/modules/email/config/schema/email.schema.yml
index c5b54d0..6e5a6c8 100644
--- a/core/modules/email/config/schema/email.schema.yml
+++ b/core/modules/email/config/schema/email.schema.yml
@@ -7,12 +7,11 @@ field.email.settings:
     - type: string
 
 field.email.instance_settings:
-  type: mapping
+  type: sequence
   label: 'E-mail settings'
-  mapping:
-    user_register_form:
-      type: boolean
-      label: 'Display on user registration form.'
+  sequence:
+    - type: string
+      label: 'Setting'
 
 field.email.value:
   type: sequence