Mention float-debug-proxy

docs/access.md

@@ -80,6 +80,10 @@ There is still some minimal setup required on the client (to establish
 the proxy connection), but that's a lot easier to manage across
 multiple platforms than a VPN client.
 
+Float implements this in testing environments, with the (publicly
+accessible) SOCKS5 proxy
+[float-debug-proxy](https://git.autistici.org/ai3/tools/float-debug-proxy).
+
 ## Authenticated reverse proxy
 
 Another alternative could be to just make everything "public", and put