Depends on what you mean by “formal”, and on what timescale, but this group will be a consumer of the “unsafe guidelines WG”, and we would eventually like to formalize such a thing. Some of the participants in this WG would be the ones interested in doing this work.
With mere “guidelines”, there is no practical, unambiguous way to establish without a shadow of doubt that a function implemented using unsafe Rust upholds the safety guarantees of safe Rust.
So I want a proper formal semantics, maybe not for all of Rust, but at least for a fragment interesting enough to express lifetime and mutability concerns. In particular, I want a formal account of interior mutability.
In open source, some people wear many hats :)