Do you mean HACL* / ValeCrypt / EverCrypt?

A number of projects like Firefox and the Linux kernel uses them. It's boring at that point. The generated code is C and assembly can be used like any library, but it has been formally verified.

But, there is ring and rustls too. A number of projects are shifting to it

Hah, I meant ocaml-tls which I think is still the most mature option in this space. But yeah there are other approaches.