diff --git a/91.md b/91.md
index 582a1d23..baf84249 100644
--- a/91.md
+++ b/91.md
@@ -14,8 +14,6 @@ An extended EOSE is an EOSE message, with the 2nd parameter being the "extension
 
 An EOSE extension is a field in the extensions object. This may contain any value.
 
-Experimental extensions SHOULD use the `x_` prefix for the object key.
-
 Clients MUST NOT rely on relays implementing any extensions.
 
 ## Extensions