diff --git a/packages/docusaurus-cssnano-preset/src/index.ts b/packages/docusaurus-cssnano-preset/src/index.ts
index 0fe88c3073..c3f4927d9f 100644
--- a/packages/docusaurus-cssnano-preset/src/index.ts
+++ b/packages/docusaurus-cssnano-preset/src/index.ts
@@ -13,6 +13,7 @@ const preset: typeof advancedBasePreset = function preset(opts) {
   const advancedPreset = advancedBasePreset({
     autoprefixer: {add: false},
     discardComments: {removeAll: true},
+    // See CodeBlock custom line number bug: https://github.com/facebook/docusaurus/pull/11487
     /* cSpell:ignore Idents */
     reduceIdents: {counter: false},
     /* cSpell:ignore zindex */