diff --git a/core/modules/taxonomy/config/schema/taxonomy.schema.yml b/core/modules/taxonomy/config/schema/taxonomy.schema.yml
index b2eb4a5..a0df268 100644
--- a/core/modules/taxonomy/config/schema/taxonomy.schema.yml
+++ b/core/modules/taxonomy/config/schema/taxonomy.schema.yml
@@ -44,6 +44,9 @@ field.taxonomy_term_reference.settings:
   type: mapping
   label: 'Taxonomy term reference settings'
   mapping:
+    options_list_callback:
+      type: string
+      label: 'Optional list callback'
     allowed_values:
       type: sequence
       label: 'Allowed values'
@@ -59,12 +62,11 @@ field.taxonomy_term_reference.settings:
               value: 'Parent'
 
 field.taxonomy_term_reference.instance_settings:
-  type: mapping
+  type: sequence
   label: 'Taxonomy term reference settings'
-  mapping:
-    user_register_form:
-      type: boolean
-      label: 'Display on user registration form.'
+  sequence:
+    - type: string
+      label: 'Setting'
 
 field.taxonomy_term_reference.value:
   type: sequence