I know this topic is old by now, but the official bitwarden server is pretty heavy-weight for selfhosting (mssql db, needs >1gb just to start),so some people thought they could do better. This seems to go well because bitwarden is completely open source. But bitwarden_rs is not affiliated with bitwarden and is missing some features from the official version. The bitwarden team seems to also look out for those alternative solutions a bit, notifying them about breaking APIs and so on.

What does this have to do with anything any why do you expect op knows about it? Also why is it important that its (RUST!!!!)?

It seems a fair place to ask about it, IMO. I doubt they are expecting that only the OP will answer, there seems to be plenty of rust proponents on here.