diff --git a/core/modules/system/config/system.schema.yml b/core/modules/system/config/system.schema.yml
index 5b73d3f..0f4301f 100644
--- a/core/modules/system/config/system.schema.yml
+++ b/core/modules/system/config/system.schema.yml
@@ -62,6 +62,28 @@ mail:
       type: text
       label: "Body"
 
+# Date format with name, pattern
+date_format:
+  type: mapping
+  label: "Date Format"
+  mapping:
+    "name":
+      type: "string"
+      label: "Format name"
+    "pattern":
+      type: mapping
+      label: "Patterns"
+      mapping:
+        "php":
+          type: "string"
+          label: "PHP date format"
+        "intl":
+          type: "string"
+          label: "International"
+    "locked":
+      type: boolean
+      label: "Locked"
+
 # Schema for configuration files of system module:
 system.site:
   type: mapping
@@ -91,6 +113,7 @@ system.site:
     "weight_select_max":
       type: integer
 
+# System maintenance settings
 system.maintenance:
   type: mapping
   label: 'Maintenance mode'
@@ -153,205 +176,35 @@ system.date:
       label: "Date formats"
       mapping:
         "long":
-          type: mapping
+          type: date_format
           label: "Long format"
-          mapping:
-            "name":
-              type: "string"
-              label: "Long format name"
-            "pattern":
-              type: mapping
-              label: "pattern"
-              mapping:
-                "php"
-                  type: "string"
-                  label: "PHP date format"
-                "intl"
-                  type: "string"
-                  label: "International"
-              "locked"
-                type: boolean
-                label: "Locked"
         "medium":
-          type: mapping
+          type: date_format
           label: "Medium format"
-          mapping:
-            "name":
-              type: "string"
-              label: "Medium format name"
-            "pattern":
-              type: mapping
-              label: "Pattern"
-              mapping:
-                "php"
-                  type: "string"
-                  label: "PHP date format"
-                "intl"
-                  type: "string"
-                  label: "International"
-              "locked"
-                type: boolean
-                label: "Locked"
         "short":
-          type: mapping
+          type: date_format
           label: "Short format"
-          mapping:
-            "name":
-              type: "string"
-              label: "Short format name"
-            "pattern":
-              type: mapping
-              label: "Pattern"
-              mapping:
-                "php"
-                  type: "string"
-                  label: "PHP date format"
-                "intl"
-                  type: "string"
-                  label: "International"
-              "locked"
-                type: boolean
-                label: "Locked"
         "html_datetime":
-          type: mapping
+          type: date_format
           label: "HTML datetime"
-          mapping:
-            "name":
-              type: "string"
-              label: "HTML datetime format name"
-            "pattern":
-              type: mapping
-              label: "Pattern"
-              mapping:
-                "php"
-                  type: "string"
-                  label: "PHP date format"
-                "intl"
-                  type: "string"
-                  label: "International"
-              "locked"
-                type: boolean
-                label: "Locked"
         "html_date":
-          type: mapping
+          type: date_format
           label: "HTML date"
-          mapping:
-            "name":
-              type: "string"
-              label: "HTML date format name"
-            "pattern":
-              type: mapping
-              label: "Pattern"
-              mapping:
-                "php"
-                  type: "string"
-                  label: "PHP date format"
-                "intl"
-                  type: "string"
-                  label: "International"
-              "locked"
-                type: boolean
-                label: "Locked"
         "html_time":
-          type: mapping
+          type: date_format
           label: "HTML time"
-          mapping:
-            "name":
-              type: "string"
-              label: "HTML time format name"
-            "pattern":
-              type: mapping
-              label: "Pattern"
-              mapping:
-                "php"
-                  type: "string"
-                  label: "PHP date format"
-                "intl"
-                  type: "string"
-                  label: "International"
-              "locked"
-                type: boolean
-                label: "Locked"
         "html_yearless_date":
-          type: mapping
+          type: date_format
           label: "HTML yearless date"
-          mapping:
-            "name":
-              type: "string"
-              label: "HTML yearless date format name"
-            "pattern":
-              type: mapping
-              label: "Pattern"
-              mapping:
-                "php"
-                  type: "string"
-                  label: "PHP date format"
-                "intl"
-                  type: "string"
-                  label: "International"
-              "locked"
-                type: boolean
-                label: "Locked"
         "html_week":
-          type: mapping
+          type: date_format
           label: "HTML week"
-          mapping:
-            "name":
-              type: "string"
-              label: "HTML week name"
-            "pattern":
-              type: mapping
-              label: "Pattern"
-              mapping:
-                "php"
-                  type: "string"
-                  label: "PHP date format"
-                "intl"
-                  type: "string"
-                  label: "International"
-              "locked"
-                type: boolean
-                label: "Locked"
         "html_month":
-          type: mapping
+          type: date_format
           label: "HTML month"
-          mapping:
-            "name":
-              type: "string"
-              label: "HTML month name"
-            "pattern":
-              type: mapping
-              label: "Pattern"
-              mapping:
-                "php"
-                  type: "string"
-                  label: "PHP date format"
-                "intl"
-                  type: "string"
-                  label: "International"
-              "locked"
-                type: boolean
-                label: "Locked"
         "html_year":
-          type: mapping
+          type: date_format
           label: "HTML year"
-          mapping:
-            "name":
-              type: "string"
-              label: "HTML year format name"
-            "pattern":
-              type: mapping
-              label: "Pattern"
-              mapping:
-                "php"
-                  type: "string"
-                  label: "PHP date format"
-                "intl"
-                  type: "string"
-                  label: "International"
-              "locked"
-                type: boolean
-                label: "Locked"
 
 # System fast 404
 system.fast_404:
@@ -407,47 +260,47 @@ system.performance:
       type: mapping
       label: "Cache"
       mapping:
-        "page"
+        "page":
           type: mapping
           label: "Page cache"
           mapping:
-            "enabled"
+            "enabled":
               type: boolean
               label: "Page cache enabled"
-            "max_age"
+            "max_age":
               type: integer
               label: "Max age of page cache"
-    "css"
+    "css":
       type: mapping
       label: "CSS performance settings"
       mapping:
-        "preprocess"
+        "preprocess":
           type: boolean
           label: "CSS preprocess"
-        "gzip"
+        "gzip":
           type: boolean
           label: "CSS gzip"
-    "js"
+    "js":
       type: mapping
       label: "JS performance settings"
       mapping:
-        "preprocess"
+        "preprocess":
           type: boolean
           label: "JS preprocess"
-        "gzip"
+        "gzip":
           type: boolean
           label: "JS gzip"
-    "response"
+    "response":
       type: mapping
       label: "Cached page compression"
       mapping:
-        "gzip"
+        "gzip":
           type: boolean
           label: "Cached page gzip"
-    "stale_file_threshold"
+    "stale_file_threshold":
       type: integer
-      label:"Stale file threshold"
-    "theme_link"
+      label: "Stale file threshold"
+    "theme_link":
       type: boolean
       label: "Theme link"
 
@@ -460,17 +313,17 @@ system.rss:
       type: mapping
       label: "RSS channel"
       mapping:
-        "description"
+        "description":
           type: string
           label: "RSS description"
-    "items"
+    "items":
       type: mapping
       label: "RSS items"
       mapping:
-        "limit"
+        "limit":
           type: integer
           description: "RSS item limit"
-        "view_mode"
+        "view_mode":
           type: string
           description: "RSS view mode"
 
@@ -496,13 +349,14 @@ system.timezone:
       label: "Default timezone settings"
     "user":
       type: mapping
-        "configurable"
+      mapping:
+        "configurable":
           type: boolean
           label: "User configurable timezones"
-        "default"
+        "default":
           type: integer
           label: "Default timezone setting at registration"
-        "warn"
+        "warn":
           type: boolean
           label: "Warn user of NULL timezone"