diff --git a/third_party/highlight/init.js b/third_party/highlight/init.js
index 66ce4773c3..7700ee6342 100644
--- a/third_party/highlight/init.js
+++ b/third_party/highlight/init.js
@@ -1 +1,24 @@
+hljs.configure({
+  // The list of languages that may be used in the auto-detection.
+  // NOTE: always derive this list from the `readme.md`.
+  languages: [
+    'bash',
+    'c',
+    'css',
+    'dart',
+    'diff',
+    'java',
+    'javascript',
+    'json',
+    'kotlin',
+    // removal reason: https://github.com/highlightjs/highlight.js/issues/4279#issuecomment-3126165923
+    // 'markdown',
+    'objectivec',
+    'plaintext',
+    'shell',
+    'swift',
+    'xml',
+    'yaml',
+  ]
+});
 hljs.highlightAll();
diff --git a/third_party/highlight/readme.md b/third_party/highlight/readme.md
index 1365cc5023..ee020ffea8 100644
--- a/third_party/highlight/readme.md
+++ b/third_party/highlight/readme.md
@@ -10,6 +10,8 @@
 4. Verify that the listed language are selected.
 5. Download and extract assets.
 
+**NOTE:** when updating this list, also update the `init.js`.
+
 ```javascript
 var selected = [
   'bash',