diff --git a/doc/PROTOCOL-WEB.md b/doc/PROTOCOL-WEB.md
index c3f9169b331b1d..080b0b6c1c8aac 100644
--- a/doc/PROTOCOL-WEB.md
+++ b/doc/PROTOCOL-WEB.md
@@ -48,7 +48,12 @@ Content-Type
 HTTP wire protocols
 
 1. support any HTTP/*, with no dependency on HTTP/2 specific framing
-2. use lower-case header/trailer names
+2. send lower-case header/trailer names over HTTP/2 (following [RFC
+   9113](https://www.rfc-editor.org/rfc/rfc9113#section-8.2-2)), send
+   header/trailer names using any case over HTTP/1.1 (following [RFC
+   9110](https://www.rfc-editor.org/rfc/rfc9112.html#section-5-1)), and compare
+   header/trailer names case-insensitively (following [RFC
+   9110](https://www.rfc-editor.org/rfc/rfc9110.html#section-5.1-3))
 3. use EOF (end of body) to close the stream
 
 ---