wordsmithing

draft-ietf-quic-http.md

@@ -415,9 +415,9 @@ before, after, or interleaved with the frames of a response message. These
 PUSH_PROMISE frames are not part of the response; see {{server-push}} for more
 details.
 
-Reserved frames ({{frame-grease}}) or frames of types not defined in this
-document MAY be sent on a request or push stream before, after, or interleaved
-with other frames described in this section.
+Frames of unknown types ({{extensions}}), including reserved frames
+({{frame-grease}}) MAY be sent on a request or push stream before, after, or
+interleaved with other frames described in this section.
 
 The HEADERS and PUSH_PROMISE frames might reference updates to the QPACK dynamic
 table. While these updates are not directly part of the message exchange, they