diff --git a/css-highlight-api-1/Overview.bs b/css-highlight-api-1/Overview.bs
index 76f30f66ebc..21f9eb3c410 100644
--- a/css-highlight-api-1/Overview.bs
+++ b/css-highlight-api-1/Overview.bs
@@ -481,6 +481,8 @@ Range Updating and Invalidation</h3>
 	the user agent must not adjust the [=boundary points=] of {{StaticRange}}s
 	in response to DOM changes,
 	nor can they be modified by the author after creation.
+	The user agent is expected to store the actual {{StaticRange}}s, rather than backing
+	them up with live {{Range}}s.
 
 	<div class=advisement>
 		Updating all {{Range}} objects as the DOM is modified