diff --git a/src/node/build/bundle.ts b/src/node/build/bundle.ts
index aabfe3e4..6eee911d 100644
--- a/src/node/build/bundle.ts
+++ b/src/node/build/bundle.ts
@@ -15,6 +15,7 @@ import { escapeRegExp, sanitizeFileName, slash } from '../shared'
 import { task } from '../utils/task'
 import { buildMPAClient } from './buildMPAClient'
 
+// https://github.com/vitejs/vite/blob/d2aa0969ee316000d3b957d7e879f001e85e369e/packages/vite/src/node/plugins/splitVendorChunk.ts#L14
 const CSS_LANGS_RE =
   /\.(css|less|sass|scss|styl|stylus|pcss|postcss|sss)(?:$|\?)/