diff --git a/rust/src/rendezvous/mod.rs b/rust/src/rendezvous/mod.rs
index 0f1e97efbd..55df0203f3 100644
--- a/rust/src/rendezvous/mod.rs
+++ b/rust/src/rendezvous/mod.rs
@@ -292,6 +292,7 @@ impl RendezvousHandler {
         // Even though this isn't mandated by the MSC, we set a Content-Type on the response. It
         // doesn't do any harm as the body is empty, but this helps escape a bug in some reverse
         // proxy/cache setup which strips the ETag header if there is no Content-Type set.
+        // Specifically, we noticed this behaviour when placing Synapse behind Cloudflare.
         response.headers_mut().typed_insert(ContentType::text());
 
         http_response_to_twisted(twisted_request, response)?;