This is a workaround to add an uninterpreted specification of Deref trait, as Deref is included in Verus but does not have spec functions.
It is currently not used, and we do not recommend using it, as it adds assumptions about the core of Rust’s deref semantics, which may cause soundness issues if not used carefully.
It may change if Verus adds native support for spec functions in the Deref trait.