diff --git a/core/modules/system/config/schema/system.schema.yml b/core/modules/system/config/schema/system.schema.yml
index 2a9c752..f664110 100644
--- a/core/modules/system/config/schema/system.schema.yml
+++ b/core/modules/system/config/schema/system.schema.yml
@@ -120,15 +120,11 @@ system.date_format.*:
         - type: string
           label: 'Language'
     pattern:
-      type: mapping
-      label: 'Format string'
-      mapping:
-        php:
-          type: string
-          label: 'PHP date format'
-        intl:
-          type: string
-          label: 'Intl date format'
+      type: sequence
+      label: 'Format'
+      sequence:
+        - type: string
+          label: 'Format string'
     langcode:
       type: string
       label: 'Default language'