Stoat.
https://stoat.chat/
https://github.com/stoatchat
Looks like a self hostable chat server. The server is written in rust and the clients in typescript and nodejs. It has client implementations for android, iOS, web, electron (win, linux, macos; x64 + arm). Text only, voice is planned.
I would have appreciated a short description about the product in op, neither stoat nor revolt are particularly helpful to guess what's it used for.