Issue #2031219 by deneo, crowdcg: Remove theme_link from system.performance.yml

core/modules/system/config/schema/system.schema.yml

@@ -256,9 +256,6 @@ system.performance:
     stale_file_threshold:
       type: integer
       label: 'Stale file threshold'
-    theme_link:
-      type: boolean
-      label: 'Force inline link rendering'
 
 system.rss:
   type: mapping

core/modules/system/config/system.performance.yml

@@ -16,4 +16,3 @@ js:
 response:
   gzip: false
 stale_file_threshold: 2592000
-theme_link: true

core/modules/system/system.install

@@ -1875,17 +1875,6 @@ function system_update_8042() {
   \Drupal::moduleHandler()->install(array('entity'));
 }
 
-/**
- * Move system theme settings from variable to config.
- *
- * @ingroup config_upgrade
- */
-function system_update_8043() {
-  update_variables_to_config('system.performance', array(
-    'theme_link' => 'theme_link',
-  ));
-}
-
 /**
  * Move system fast 404 settings from variable to config.
  *