diff --git a/components/script/dom/window.rs b/components/script/dom/window.rs
index ef992379307..37bf817ed7a 100644
--- a/components/script/dom/window.rs
+++ b/components/script/dom/window.rs
@@ -1453,7 +1453,10 @@ impl Window {
 
     pub fn freeze(&self) {
         self.upcast::<GlobalScope>().suspend();
-        // A hint to the JS runtime that now would be a good time to GC this window.
+        // A hint to the JS runtime that now would be a good time to
+        // GC any unreachable objects generated by user script,
+        // or unattached DOM nodes. Attached DOM nodes can't be GCd yet,
+        // as the document might be thawed later.
         self.Gc();
     }