changelog(gateway-over-libp2p): add gateway-over-libp2p changelog

docs/changelogs/v0.23.md

@@ -10,6 +10,7 @@
   - [Gateway: meaningful CAR responses on Not Found errors](#gateway-meaningful-car-responses-on-not-found-errors)
   - [Binary characters in file names: no longer works with old clients and new Kubo servers](#binary-characters-in-file-names-no-longer-works-with-old-clients-and-new-kubo-servers)
   - [Self-hosting `/routing/v1` endpoint for delegated routing needs](#self-hosting-routingv1-endpoint-for-delegated-routing-needs)
+  - [Gateway Over Libp2p Experiment](#gateway-over-libp2p-experiment)
 - [📝 Changelog](#-changelog)
 - [👨‍👩‍👧‍👦 Contributors](#-contributors)
 
@@ -67,6 +68,20 @@ HTTP [Routing V1](https://specs.ipfs.tech/routing/http-routing-v1/) API endpoint
 self-hosting and experimentation with custom delegated routers. This is disabled by default,
 but can be enabled by setting [`Gateway.ExposeRoutingAPI`](https://github.com/ipfs/kubo/blob/master/docs/config.md#gatewayexposeroutingapi) to `true` .
 
+#### Gateway Over Libp2p Experiment
+
+It is now possible to serve [Trustless Gateway API](https://specs.ipfs.tech/http-gateways/trustless-gateway/) responses
+such as for blocks and CARs over libp2p. This takes advantage of the [specification work](https://github.com/libp2p/specs/pull/508)
+in libp2p expanding beyond the basics of performing HTTP requests over libp2p streams that have been available in libp2p
+and in kubo experimental features such as [p2p-http-proxy](https://github.com/ipfs/kubo/blob/master/docs/experimental-features.md#p2p-http-proxy).
+
+This means that implementations that want to use the Trustless Gateway API as a data transport mechanism can do so even
+when standard HTTP transports would fail (e.g. when the endpoint is behind a firewall, or wants to serve data to a browser
+but does not have a CA certificate).
+
+See [HTTP Gateway over Libp2p](https://github.com/ipfs/kubo/blob/master/docs/experimental-features.md#http-gateway-over-libp2p)
+for more details.
+
 ### 📝 Changelog
 
 ### 👨‍👩‍👧‍👦 Contributors