diff --git a/fetch/api/request/request-idl.html b/fetch/api/request/request-idl.html
index f78f0ca894ae2b..f7833779ce25ac 100644
--- a/fetch/api/request/request-idl.html
+++ b/fetch/api/request/request-idl.html
@@ -15,9 +15,7 @@
       typedef any JSON;
       typedef (Blob or BufferSource or FormData or URLSearchParams or USVString) BodyInit;
 
-      [NoInterfaceObject,
-      Exposed=(Window,Worker)]
-      interface Body {
+      interface mixin Body {
         readonly attribute ReadableStream? body;
         readonly attribute boolean bodyUsed;
         [NewObject] Promise<ArrayBuffer> arrayBuffer();
@@ -48,7 +46,7 @@
 
         [NewObject] Request clone();
       };
-      Request implements Body;
+      Request includes Body;
 
       dictionary RequestInit {
         ByteString method;
diff --git a/fetch/api/response/response-idl.html b/fetch/api/response/response-idl.html
index 3bbf54e6f3c15c..bd265fa203dccf 100644
--- a/fetch/api/response/response-idl.html
+++ b/fetch/api/response/response-idl.html
@@ -15,9 +15,7 @@
       typedef any JSON;
       typedef (Blob or BufferSource or FormData or URLSearchParams or USVString) BodyInit;
 
-      [NoInterfaceObject,
-      Exposed=(Window,Worker)]
-      interface Body {
+      interface mixin Body {
         readonly attribute ReadableStream? body;
         readonly attribute boolean bodyUsed;
         [NewObject] Promise<ArrayBuffer> arrayBuffer();
@@ -45,7 +43,7 @@
 
         [NewObject] Response clone();
       };
-      Response implements Body;
+      Response includes Body;
 
       dictionary ResponseInit {
         unsigned short status = 200;