core/config/schema/core.data_types.schema.yml              | 1 +
 core/modules/system/config/install/system.theme.global.yml | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/core/config/schema/core.data_types.schema.yml b/core/config/schema/core.data_types.schema.yml
index 4476e98d0c..0212b7ee2c 100644
--- a/core/config/schema/core.data_types.schema.yml
+++ b/core/config/schema/core.data_types.schema.yml
@@ -206,6 +206,7 @@ theme_settings:
           label: 'Logo path'
         url:
           type: uri
+          nullable: true
           label: 'URL'
         use_default:
           type: boolean
diff --git a/core/modules/system/config/install/system.theme.global.yml b/core/modules/system/config/install/system.theme.global.yml
index b8da4238c2..598d6bd0cd 100644
--- a/core/modules/system/config/install/system.theme.global.yml
+++ b/core/modules/system/config/install/system.theme.global.yml
@@ -10,5 +10,5 @@ features:
   node_user_picture: true
 logo:
   path: ''
-  url: ''
+  url: ~
   use_default: true