This seems to be a successor to CCured from 2005, a project partially funded by Microsoft. [1]
The general idea is straightforward: "The unchecked C pointer type * is kept and three new checked pointer types are added: one for pointers that are never used in pointer arithmetic and do not need bounds checking (ptr), one for array pointer types that are involved in pointer arithmetic and need bounds checking (array ptr), and one for pointer types that carry their bounds with them dynamically (span)." So this is really a new language derived from C, to which programs can be converted.
This is basically a good idea, but it's only useful if pushed hard by somebody like Microsoft. People won't convert without heavy pressure.