diff --git a/doc/PROTOCOL-HTTP2.md b/doc/PROTOCOL-HTTP2.md
index 18803f2a097..2df1c74beef 100644
--- a/doc/PROTOCOL-HTTP2.md
+++ b/doc/PROTOCOL-HTTP2.md
@@ -153,6 +153,7 @@ DATA (flags = END_STREAM)
 HEADERS (flags = END_HEADERS)
 :status = 200
 grpc-encoding = gzip
+content-type = application/grpc+proto
 
 DATA
 <Length-Prefixed Message>