I've just published a protoXEP to expose a lot of information on data policy, as part of my current @nlnet grant. The plan is to have services (XMPP server, gateways, etc) expose to clients how long they keep data, if they encrypt, how they handle authentication, who can access data, what is backup frequency, where data are located, etc.
This is very precious information when you use a service.
I now want to expose in a easy way this to end-users.