docs: more tips around privacy stuff

README.md

@@ -24,6 +24,16 @@
 
 ## Tips & Tricks
 
+### Disabling federation
+
+> We're not sure this does it exactly and there is still a discussion running
+> upstrem about whether this is the right way to do it & whether it could be
+> more convenient. We welcome issues / change sets to close up more federation
+> functionality.
+
+- use `DISABLE_FEDERATION=1` to turn off federation listeners
+- don't use [`compose.matrix.yml`](https://git.coopcloud.tech/coop-cloud/traefik/src/branch/master/compose.matrix.yml) in your traefik config to keep the federation ports closed
+
 ### Seeing what changed in `homeserver.yaml` between versions
 
 Change the version range to suit your needs.
@@ -57,3 +67,9 @@ docker run -it \
   matrixdotorg/synapse:v1.48.0 \
   sh -c '/start.py generate; cat /data/foo.com.log.config' > log.config
 ```
+
+### Getting client discovery on a custom domain
+
+You'll need to deploy something like [this](https://git.autonomic.zone/ruangrupa/well-known-uris).
+
+This could be implemented in this recipe but we haven't merged it in yet. Chang sets are welcome.