That's right, but I know several project maintainers who are looking moving to it because BoringSSL's scope is smaller and is sufficient for their projects' needs. That's why I think the BoringSSL's API status will evolve with time. And Ring is based on it, so...
Then there's ocaml-tls which aims to provide a drop-in implementation of the OpenSSL API too.
We're finally seeing much activibity, and in that sense, I'm glad that Heartbleed happened, but it should have been earlier :).
Google don't recommend you do this.
https://boringssl.googlesource.com/boringssl/
> which deliberately removed most stuff, more than LibreSSLLibreSSL has taken fixes from BoringSSL but it has the aim of maintaining API compatibility to the point where most applications using OpenSSL should "just work" for the most part. I've not tried building against BoringSSL but form reading their documentation it seems like the API is very much a moving target.