diff --git a/css-animations-1/Overview.bs b/css-animations-1/Overview.bs
index 3408c98121d8..1e441c74623c 100644
--- a/css-animations-1/Overview.bs
+++ b/css-animations-1/Overview.bs
@@ -228,6 +228,8 @@ Declaring Keyframes</h2>
 	the names are fully <a>case-sensitive</a>;
 	two names are equal only if they are codepoint-by-codepoint equal.
 	The <<custom-ident>> additionally excludes the ''animation-name/none'' keyword.
+	The empty <<string>> should be parsed as invalid, any other should be serialized as <<ident>>
+	when possible, or as <<string>> otherwise (eg, <a>CSS Wide Keywords<a>).
 
 	<div class=example>
 		For example, the following two ''@keyframes'' rules have the same name,