Ferrocene has donated their specification to the project, so there absolutely is a specification now. What you can argue is that the memory model isn‘t fully defined, but it‘s almost certainly going to land somewhere around stacked borrows or tree borrows. Arguably C doesn‘t fare much better in that regard though as it doesn‘t even properly define its pointer provenance model either and Rust is much closer to defining its.

Oh something has changed in the last 6 months? glad they are making progress on the spec.