docs: unhiding HTTP/3 and adding docs

api/envoy/config/listener/v3/udp_listener_config.proto

@@ -34,7 +34,7 @@ message UdpListenerConfig {
   // Configuration for QUIC protocol. If empty, QUIC will not be enabled on this listener. Set
   // to the default object to enable QUIC without modifying any additional options.
   //
-  // .. note::
+  // .. warning::
   //   QUIC support is currently alpha and should be used with caution.
   //
   //   For known outstanding issues before Envoy QUIC support is GA, issues

api/envoy/extensions/upstreams/http/v3/http_protocol_options.proto

@@ -59,7 +59,7 @@ option (udpa.annotations.file_status).package_version_status = ACTIVE;
 // [#next-free-field: 6]
 message HttpProtocolOptions {
   // If this is used, the cluster will only operate on one of the possible upstream protocols.
-  // Note that HTTP/2 or above should generally be used for upstream clusters doing gRPC.
+  // Note that HTTP/2 or above should generally be used for upstream gRPC clusters.
   message ExplicitHttpConfig {
     oneof protocol_config {
       option (validate.required) = true;
@@ -68,7 +68,7 @@ message HttpProtocolOptions {
 
       config.core.v3.Http2ProtocolOptions http2_protocol_options = 2;
 
-      // .. note::
+      // .. warning::
       //   QUIC support is currently alpha and should be used with caution.
       //
       //   See comments :ref:`here <envoy_v3_api_field_config.listener.v3.UdpListenerConfig.quic_options>`
@@ -84,7 +84,7 @@ message HttpProtocolOptions {
 
     config.core.v3.Http2ProtocolOptions http2_protocol_options = 2;
 
-    // .. note::
+    // .. warning::
     //   QUIC support is currently alpha and should be used with caution.
     //
     //   See comments :ref:`here <envoy_v3_api_field_config.listener.v3.UdpListenerConfig.quic_options>`
@@ -112,7 +112,7 @@ message HttpProtocolOptions {
     // See :ref:`here <arch_overview_http3_upstream>` for more information on
     // when HTTP/3 will be used, and when Envoy will fail over to TCP.
     //
-    // .. note::
+    // .. warning::
     //   QUIC support is currently alpha and should be used with caution.
     //   AutoHttpConfig config is undergoing especially rapid change and as it
     //   is alpha is not guaranteed to be API-stable.

docs/root/configuration/http/http_filters/lua_filter.rst

@@ -659,7 +659,7 @@ protocol()
   streamInfo:protocol()
 
 Returns the string representation of :repo:`HTTP protocol <include/envoy/http/protocol.h>`
-used by the current request. The possible values are: *HTTP/1.0*, *HTTP/1.1*, *HTTP/2* and *HTTP/3*.
+used by the current request. The possible values are: ``HTTP/1.0``, ``HTTP/1.1``, ``HTTP/2`` and ``HTTP/3*``.
 
 downstreamLocalAddress()
 ^^^^^^^^^^^^^^^^^^^^^^^^

docs/root/configuration/upstream/cluster_manager/cluster_runtime.rst

@@ -140,11 +140,11 @@ upstream.healthy_panic_threshold
   Defaults to 50%.
 
 upstream.use_http2
-  Whether the cluster uses *http2* if configured in `HttpProtocolOptions <envoy_v3_msg_config.upstreams.http.v3.HttpProtocolOptions>`.
+  Whether the cluster uses ``HTTP/2`` if configured in `HttpProtocolOptions <envoy_v3_msg_config.upstreams.http.v3.HttpProtocolOptions>`.
   Set to 0 to disable HTTP/2 even if the feature is configured. Defaults to enabled.
 
 upstream.use_http3
-  Whether the cluster uses *http3* if configured in `HttpProtocolOptions <envoy_v3_msg_config.upstreams.http.v3.HttpProtocolOptions>`.
+  Whether the cluster uses ``HTTP/3`` if configured in `HttpProtocolOptions <envoy_v3_msg_config.upstreams.http.v3.HttpProtocolOptions>`.
   Set to 0 to disable HTTP/3 even if the feature is configured. Defaults to enabled.
 
 

docs/root/faq/configuration/timeouts.rst

@@ -60,7 +60,7 @@ context request/stream is interchangeable.
   is the amount of time that the connection manager will allow a stream to exist with no upstream
   or downstream activity. The default stream idle timeout is *5 minutes*. This timeout is strongly
   recommended for all requests (not just streaming requests/responses) as it additionally defends
-  against a peer that does not open stream window once an entire response has been buffered
+  against a peer that does not open the stream window once an entire response has been buffered
   to be sent to a downstream client.
 * The HTTP protocol :ref:`max_stream_duration <envoy_v3_api_field_config.core.v3.HttpProtocolOptions.max_stream_duration>`
   is defined in a generic message used by the HTTP connection manager. The max stream duration is the

docs/root/intro/arch_overview/http/http3.rst

@@ -1,7 +1,10 @@
 .. _arch_overview_http3:
 
+HTTP3 overview
+==============
+
 HTTP3 downstream
-================
+----------------
 
 HTTP/3 downstream support is still in Alpha, and should be used with caution.
 Outstanding issues required for HTTP/3 to go GA can be found
@@ -14,7 +17,7 @@ ensuring the downstream transport socket is a QuicDownstreamTransport.
 See example :repo:`downstream HTTP/3 configuration </configs/envoyproxy_io_proxy_http3_downstream.template.yaml1>` for example configuration.
 
 Note that the example configuration includes both a TCP and a UDP listener, and the TCP
-listener is advertising http/3 support via an alt-svc header. Advertising HTTP/3 is not necessary for
+listener is advertising http/3 support via an ``alt-svc header``. Advertising HTTP/3 is not necessary for
 in-house deployments where HTTP/3 is explicitly configured, but is needed for internet facing deployments
 where TCP is the default, and clients such as Chrome will only attempt HTTP/3 if it is explicitly advertised.
 
@@ -24,7 +27,7 @@ use BPF by default if multiple worker threads are configured, but may require ro
 (e.g. sudo setcap cap_bpf+ep). Envoy will log a warning on start-up if BPF is attempted and fails.
 
 HTTP3 upstream
-===============
+--------------
 
 HTTP/3 upstream support is still in Alpha, and should be used with caution.
 Outstanding issues required for HTTP/3 to go GA can be found

docs/root/intro/deployment_types/service_to_service.rst

@@ -14,7 +14,7 @@ Service to service egress listener
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 This is the port used by applications to talk to other services in the infrastructure. For example,
-*http://localhost:9001*. HTTP and gRPC requests use the HTTP/1.1 *host* header or the HTTP/2 or HTTP/3
+http://localhost:9001. HTTP and gRPC requests use the HTTP/1.1 *host* header or the HTTP/2 or HTTP/3
 *:authority* header to indicate which remote cluster the request is destined for. Envoy handles
 service discovery, load balancing, rate limiting, etc. depending on the details in the
 configuration. Services only need to know about the local Envoy and do not need to concern