core/modules/file/config/install/file.settings.yml  | 1 +
 core/modules/file/config/schema/file.schema.yml     | 3 +++
 core/modules/system/config/install/system.file.yml  | 1 -
 core/modules/system/config/schema/system.schema.yml | 2 ++
 4 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/core/modules/file/config/install/file.settings.yml b/core/modules/file/config/install/file.settings.yml
index 9191a0b..986f360 100644
--- a/core/modules/file/config/install/file.settings.yml
+++ b/core/modules/file/config/install/file.settings.yml
@@ -1,3 +1,4 @@
+temporary_maximum_age: 21600
 description:
   type: 'textfield'
   length: 128
diff --git a/core/modules/file/config/schema/file.schema.yml b/core/modules/file/config/schema/file.schema.yml
index 42d57d9..1ba7e0a 100644
--- a/core/modules/file/config/schema/file.schema.yml
+++ b/core/modules/file/config/schema/file.schema.yml
@@ -4,6 +4,9 @@ file.settings:
   type: config_object
   label: 'File settings'
   mapping:
+    temporary_maximum_age:
+      type: integer
+      label: 'Maximum age for temporary files'
     description:
       type: mapping
       label: 'Description'
diff --git a/core/modules/system/config/install/system.file.yml b/core/modules/system/config/install/system.file.yml
index ec8c053..4cbcbcd 100644
--- a/core/modules/system/config/install/system.file.yml
+++ b/core/modules/system/config/install/system.file.yml
@@ -2,4 +2,3 @@ allow_insecure_uploads: false
 default_scheme: 'public'
 path:
   temporary: ''
-temporary_maximum_age: 21600
diff --git a/core/modules/system/config/schema/system.schema.yml b/core/modules/system/config/schema/system.schema.yml
index a6f61b6..2dfb855 100644
--- a/core/modules/system/config/schema/system.schema.yml
+++ b/core/modules/system/config/schema/system.schema.yml
@@ -278,6 +278,8 @@ system.file:
         temporary:
           type: string
           label: 'Temporary directory'
+    # @deprecated in Drupal 8.4.x and will be removed before Drupal 9.0.0.
+    # @see https://www.drupal.org/node/2894194
     temporary_maximum_age:
       type: integer
       label: 'Maximum age for temporary files'